diff --git a/Externals/enet/enet.vcxproj b/Externals/enet/enet.vcxproj
index 71e0086faf..ac6fe790b1 100644
--- a/Externals/enet/enet.vcxproj
+++ b/Externals/enet/enet.vcxproj
@@ -61,6 +61,7 @@
   <ImportGroup Label="PropertySheets">
     <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
     <Import Project="..\..\Source\VSProps\Base.props" />
+    <Import Project="..\..\Source\VSProps\ClDisableAllWarnings.props" />
   </ImportGroup>
   <PropertyGroup Label="UserMacros" />
   <PropertyGroup />
diff --git a/Source/Core/AudioCommon/XAudio2Stream.cpp b/Source/Core/AudioCommon/XAudio2Stream.cpp
index 12954fc5bf..69c503f310 100644
--- a/Source/Core/AudioCommon/XAudio2Stream.cpp
+++ b/Source/Core/AudioCommon/XAudio2Stream.cpp
@@ -25,8 +25,7 @@ private:
 
 public:
   StreamingVoiceContext(IXAudio2* pXAudio2, CMixer* pMixer, Common::Event& pSyncEvent);
-
-  ~StreamingVoiceContext();
+  virtual ~StreamingVoiceContext();
 
   void Stop();
   void Play();
diff --git a/Source/Core/AudioCommon/XAudio2_7Stream.cpp b/Source/Core/AudioCommon/XAudio2_7Stream.cpp
index 06fb645c95..1abf6d2096 100644
--- a/Source/Core/AudioCommon/XAudio2_7Stream.cpp
+++ b/Source/Core/AudioCommon/XAudio2_7Stream.cpp
@@ -25,8 +25,7 @@ private:
 
 public:
   StreamingVoiceContext2_7(IXAudio2* pXAudio2, CMixer* pMixer, Common::Event& pSyncEvent);
-
-  ~StreamingVoiceContext2_7();
+  virtual ~StreamingVoiceContext2_7();
 
   void Stop();
   void Play();
diff --git a/Source/Core/Common/Config/Section.h b/Source/Core/Common/Config/Section.h
index 8b36ce157e..0a4662d156 100644
--- a/Source/Core/Common/Config/Section.h
+++ b/Source/Core/Common/Config/Section.h
@@ -27,6 +27,7 @@ class Section
 
 public:
   Section(LayerType layer, System system, const std::string& name);
+  virtual ~Section() = default;
 
   virtual bool Exists(const std::string& key) const;
   bool Delete(const std::string& key);
diff --git a/Source/Core/Common/Crypto/ec.cpp b/Source/Core/Common/Crypto/ec.cpp
index 9dca32878b..5fe7e9bb2b 100644
--- a/Source/Core/Common/Crypto/ec.cpp
+++ b/Source/Core/Common/Crypto/ec.cpp
@@ -15,6 +15,11 @@
 #include "Common/Crypto/bn.h"
 #include "Common/Crypto/ec.h"
 
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4505)
+#endif
+
 // y**2 + x*y = x**3 + x + b
 UNUSED static const u8 ec_b[30] = {0x00, 0x66, 0x64, 0x7e, 0xde, 0x6c, 0x33, 0x2c, 0x7f, 0x8c,
                                    0x09, 0x23, 0xbb, 0x58, 0x21, 0x3b, 0x33, 0x3b, 0x20, 0xe9,
@@ -404,3 +409,7 @@ void ec_priv_to_pub(const u8* k, u8* Q)
 {
   point_mul(Q, k, ec_G);
 }
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
diff --git a/Source/Core/Common/FileUtil.cpp b/Source/Core/Common/FileUtil.cpp
index ebab9e9c48..203ddbac4b 100644
--- a/Source/Core/Common/FileUtil.cpp
+++ b/Source/Core/Common/FileUtil.cpp
@@ -631,9 +631,9 @@ void CopyDir(const std::string& source_path, const std::string& dest_path)
 // Returns the current directory
 std::string GetCurrentDir()
 {
-  char* dir;
   // Get the current working directory (getcwd uses malloc)
-  if (!(dir = __getcwd(nullptr, 0)))
+  char* dir = __getcwd(nullptr, 0);
+  if (!dir)
   {
     ERROR_LOG(COMMON, "GetCurrentDirectory failed: %s", GetLastErrorMsg().c_str());
     return nullptr;
@@ -986,7 +986,7 @@ u64 IOFile::Tell() const
   if (IsOpen())
     return ftello(m_file);
   else
-    return -1;
+    return UINT64_MAX;
 }
 
 bool IOFile::Flush()
diff --git a/Source/Core/Common/GL/GLInterface/WGL.cpp b/Source/Core/Common/GL/GLInterface/WGL.cpp
index 57c46cb42b..3e500f5866 100644
--- a/Source/Core/Common/GL/GLInterface/WGL.cpp
+++ b/Source/Core/Common/GL/GLInterface/WGL.cpp
@@ -248,8 +248,8 @@ bool cInterfaceWGL::Create(void* window_handle, bool core)
     return false;
   }
 
-  int pixel_format;
-  if (!(pixel_format = ChoosePixelFormat(m_dc, &pfd)))
+  int pixel_format = ChoosePixelFormat(m_dc, &pfd);
+  if (!pixel_format)
   {
     PanicAlert("(2) Can't find a suitable PixelFormat.");
     return false;
@@ -261,7 +261,8 @@ bool cInterfaceWGL::Create(void* window_handle, bool core)
     return false;
   }
 
-  if (!(m_rc = wglCreateContext(m_dc)))
+  m_rc = wglCreateContext(m_dc);
+  if (!m_rc)
   {
     PanicAlert("(4) Can't create an OpenGL rendering context.");
     return false;
diff --git a/Source/Core/Common/MathUtil.h b/Source/Core/Common/MathUtil.h
index 7e48e38d80..becaf09792 100644
--- a/Source/Core/Common/MathUtil.h
+++ b/Source/Core/Common/MathUtil.h
@@ -198,7 +198,7 @@ inline int IntLog2(u64 val)
   return 63 - __builtin_clzll(val);
 
 #elif defined(_MSC_VER)
-  unsigned long result = -1;
+  unsigned long result = ULONG_MAX;
   _BitScanReverse64(&result, val);
   return result;
 
diff --git a/Source/Core/Common/Profiler.cpp b/Source/Core/Common/Profiler.cpp
index fdc356a164..0be14073bd 100644
--- a/Source/Core/Common/Profiler.cpp
+++ b/Source/Core/Common/Profiler.cpp
@@ -29,8 +29,8 @@ std::string Profiler::s_lazy_result = "";
 int Profiler::s_lazy_delay = 0;
 
 Profiler::Profiler(const std::string& name)
-    : m_name(name), m_usecs(0), m_usecs_min(-1), m_usecs_max(0), m_usecs_quad(0), m_calls(0),
-      m_depth(0)
+    : m_name(name), m_usecs(0), m_usecs_min(UINT64_MAX), m_usecs_max(0), m_usecs_quad(0),
+      m_calls(0), m_depth(0)
 {
   m_time = Common::Timer::GetTimeUs();
   s_max_length = std::max<u32>(s_max_length, u32(m_name.length()));
@@ -154,7 +154,7 @@ std::string Profiler::Read()
   buffer << std::setw(PROFILER_FIELD_LENGTH) << std::right << m_usecs_max;
 
   m_usecs = 0;
-  m_usecs_min = -1;
+  m_usecs_min = UINT64_MAX;
   m_usecs_max = 0;
   m_usecs_quad = 0;
   m_calls = 0;
diff --git a/Source/Core/Common/SDCardUtil.cpp b/Source/Core/Common/SDCardUtil.cpp
index 1bb09878b6..9e72990747 100644
--- a/Source/Core/Common/SDCardUtil.cpp
+++ b/Source/Core/Common/SDCardUtil.cpp
@@ -49,6 +49,11 @@
 #include <unistd.h>  // for unlink()
 #endif
 
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4310)
+#endif
+
 /* Believe me, you *don't* want to change these constants !! */
 #define BYTES_PER_SECTOR 512
 #define RESERVED_SECTORS 32
@@ -289,3 +294,7 @@ FailWrite:
     ERROR_LOG(COMMON, "unlink(%s) failed: %s", filename.c_str(), GetLastErrorMsg().c_str());
   return false;
 }
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
diff --git a/Source/Core/Common/Thread.cpp b/Source/Core/Common/Thread.cpp
index 190653ee31..fa81314795 100644
--- a/Source/Core/Common/Thread.cpp
+++ b/Source/Core/Common/Thread.cpp
@@ -62,11 +62,8 @@ void SwitchCurrentThread()
 }
 
 // Sets the debugger-visible name of the current thread.
-// Uses undocumented (actually, it is now documented) trick.
-// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vsdebug/html/vxtsksettingthreadname.asp
-
-// This is implemented much nicer in upcoming msvc++, see:
-// http://msdn.microsoft.com/en-us/library/xcb2z8hs(VS.100).aspx
+// Uses trick documented in:
+// https://docs.microsoft.com/en-us/visualstudio/debugger/how-to-set-a-thread-name-in-native-code
 void SetCurrentThreadName(const char* szThreadName)
 {
   static const DWORD MS_VC_EXCEPTION = 0x406D1388;
@@ -83,7 +80,7 @@ void SetCurrentThreadName(const char* szThreadName)
 
   info.dwType = 0x1000;
   info.szName = szThreadName;
-  info.dwThreadID = -1;  // dwThreadID;
+  info.dwThreadID = static_cast<DWORD>(-1);
   info.dwFlags = 0;
 
   __try
diff --git a/Source/Core/Core/ARDecrypt.cpp b/Source/Core/Core/ARDecrypt.cpp
index 40d43a3619..77bfc175d3 100644
--- a/Source/Core/Core/ARDecrypt.cpp
+++ b/Source/Core/Core/ARDecrypt.cpp
@@ -471,7 +471,8 @@ void DecryptARCode(std::vector<std::string> vCodes, std::vector<AREntry>* ops)
     std::transform(s.begin(), s.end(), s.begin(), toupper);
   }
 
-  if ((ret = alphatobin(uCodes, vCodes, (int)vCodes.size())))
+  ret = alphatobin(uCodes, vCodes, (int)vCodes.size());
+  if (ret)
   {
     // Return value is index + 1, 0 being the success flag value.
     PanicAlertT("Action Replay Code Decryption Error:\nParity Check Failed\n\nCulprit Code:\n%s",
diff --git a/Source/Core/Core/Config/GraphicsSettings.cpp b/Source/Core/Core/Config/GraphicsSettings.cpp
index dcde16a17d..870fb1971c 100644
--- a/Source/Core/Core/Config/GraphicsSettings.cpp
+++ b/Source/Core/Core/Config/GraphicsSettings.cpp
@@ -57,7 +57,7 @@ const ConfigInfo<bool> GFX_ENABLE_GPU_TEXTURE_DECODING{
 const ConfigInfo<bool> GFX_ENABLE_PIXEL_LIGHTING{{System::GFX, "Settings", "EnablePixelLighting"},
                                                  false};
 const ConfigInfo<bool> GFX_FAST_DEPTH_CALC{{System::GFX, "Settings", "FastDepthCalc"}, true};
-const ConfigInfo<int> GFX_MSAA{{System::GFX, "Settings", "MSAA"}, 1};
+const ConfigInfo<u32> GFX_MSAA{{System::GFX, "Settings", "MSAA"}, 1};
 const ConfigInfo<bool> GFX_SSAA{{System::GFX, "Settings", "SSAA"}, false};
 const ConfigInfo<int> GFX_EFB_SCALE{{System::GFX, "Settings", "EFBScale"},
                                     static_cast<int>(SCALE_1X)};
diff --git a/Source/Core/Core/Config/GraphicsSettings.h b/Source/Core/Core/Config/GraphicsSettings.h
index 7ff7b2b667..0b3b98ee06 100644
--- a/Source/Core/Core/Config/GraphicsSettings.h
+++ b/Source/Core/Core/Config/GraphicsSettings.h
@@ -47,7 +47,7 @@ extern const ConfigInfo<bool> GFX_INTERNAL_RESOLUTION_FRAME_DUMPS;
 extern const ConfigInfo<bool> GFX_ENABLE_GPU_TEXTURE_DECODING;
 extern const ConfigInfo<bool> GFX_ENABLE_PIXEL_LIGHTING;
 extern const ConfigInfo<bool> GFX_FAST_DEPTH_CALC;
-extern const ConfigInfo<int> GFX_MSAA;
+extern const ConfigInfo<u32> GFX_MSAA;
 extern const ConfigInfo<bool> GFX_SSAA;
 extern const ConfigInfo<int> GFX_EFB_SCALE;
 extern const ConfigInfo<bool> GFX_TEXFMT_OVERLAY_ENABLE;
diff --git a/Source/Core/Core/Debugger/Dump.cpp b/Source/Core/Core/Debugger/Dump.cpp
index 45f8fde926..a7ee736caf 100644
--- a/Source/Core/Core/Debugger/Dump.cpp
+++ b/Source/Core/Core/Debugger/Dump.cpp
@@ -42,7 +42,7 @@ u32 CDump::GetGPR(int _step, int _gpr)
   u32 offset = _step * STRUCTUR_SIZE;
 
   if (offset >= m_size)
-    return -1;
+    return UINT32_MAX;
 
   return Read32(offset + OFFSET_GPR + (_gpr * 4));
 }
@@ -52,7 +52,7 @@ u32 CDump::GetPC(int _step)
   u32 offset = _step * STRUCTUR_SIZE;
 
   if (offset >= m_size)
-    return -1;
+    return UINT32_MAX;
 
   return Read32(offset + OFFSET_PC);
 }
diff --git a/Source/Core/Core/HLE/HLE.cpp b/Source/Core/Core/HLE/HLE.cpp
index cc166768da..5fb7fac59c 100644
--- a/Source/Core/Core/HLE/HLE.cpp
+++ b/Source/Core/Core/HLE/HLE.cpp
@@ -247,8 +247,10 @@ u32 UnPatch(const std::string& patch_name)
     return addr;
   }
 
-  for (const auto& symbol : g_symbolDB.GetSymbolsFromName(patch_name))
+  const auto& symbols = g_symbolDB.GetSymbolsFromName(patch_name);
+  if (symbols.size())
   {
+    const auto& symbol = symbols[0];
     for (u32 addr = symbol->address; addr < symbol->address + symbol->size; addr += 4)
     {
       s_original_instructions.erase(addr);
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/UCodes.h b/Source/Core/Core/HW/DSPHLE/UCodes/UCodes.h
index 6cc8b45242..07dc0f3e1d 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/UCodes.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/UCodes.h
@@ -63,7 +63,7 @@ protected:
 
   CMailHandler& m_mail_handler;
 
-  enum EDSP_Codes
+  enum EDSP_Codes : u32
   {
     DSP_INIT = 0xDCD10000,
     DSP_RESUME = 0xDCD10001,
diff --git a/Source/Core/Core/HW/DVD/DVDInterface.cpp b/Source/Core/Core/HW/DVD/DVDInterface.cpp
index 2ea86942da..ee02b90533 100644
--- a/Source/Core/Core/HW/DVD/DVDInterface.cpp
+++ b/Source/Core/Core/HW/DVD/DVDInterface.cpp
@@ -349,8 +349,8 @@ static void DTKStreamingCallback(const std::vector<u8>& audio_data, s64 cycles_l
 
   // Determine which audio data to read next.
   static const int MAXIMUM_SAMPLES = 48000 / 2000 * 7;  // 3.5ms of 48kHz samples
-  u64 read_offset;
-  u32 read_length;
+  u64 read_offset = 0;
+  u32 read_length = 0;
   if (s_stream && AudioInterface::IsPlaying())
   {
     read_offset = s_audio_position;
diff --git a/Source/Core/Core/HW/EXI/BBA-TAP/TAP_Win32.cpp b/Source/Core/Core/HW/EXI/BBA-TAP/TAP_Win32.cpp
index f825f5eef6..58e497a8fb 100644
--- a/Source/Core/Core/HW/EXI/BBA-TAP/TAP_Win32.cpp
+++ b/Source/Core/Core/HW/EXI/BBA-TAP/TAP_Win32.cpp
@@ -157,7 +157,7 @@ bool OpenTAP(HANDLE& adapter, const std::basic_string<TCHAR>& device_guid)
 
   if (adapter == INVALID_HANDLE_VALUE)
   {
-    INFO_LOG(SP1, "Failed to open TAP at %s", device_path);
+    INFO_LOG(SP1, "Failed to open TAP at %s", device_path.c_str());
     return false;
   }
   return true;
diff --git a/Source/Core/Core/HW/MMIO.cpp b/Source/Core/Core/HW/MMIO.cpp
index 8ee341554d..a6dcdeebd6 100644
--- a/Source/Core/Core/HW/MMIO.cpp
+++ b/Source/Core/Core/HW/MMIO.cpp
@@ -20,14 +20,14 @@ template <typename T>
 class ReadHandlingMethod
 {
 public:
-  virtual ~ReadHandlingMethod() {}
+  virtual ~ReadHandlingMethod() = default;
   virtual void AcceptReadVisitor(ReadHandlingMethodVisitor<T>& v) const = 0;
 };
 template <typename T>
 class WriteHandlingMethod
 {
 public:
-  virtual ~WriteHandlingMethod() {}
+  virtual ~WriteHandlingMethod() = default;
   virtual void AcceptWriteVisitor(WriteHandlingMethodVisitor<T>& v) const = 0;
 };
 
@@ -39,7 +39,7 @@ class ConstantHandlingMethod : public ReadHandlingMethod<T>
 {
 public:
   explicit ConstantHandlingMethod(T value) : value_(value) {}
-  virtual ~ConstantHandlingMethod() {}
+  virtual ~ConstantHandlingMethod() = default;
   void AcceptReadVisitor(ReadHandlingMethodVisitor<T>& v) const override
   {
     v.VisitConstant(value_);
@@ -62,7 +62,7 @@ class NopHandlingMethod : public WriteHandlingMethod<T>
 {
 public:
   NopHandlingMethod() {}
-  virtual ~NopHandlingMethod() {}
+  virtual ~NopHandlingMethod() = default;
   void AcceptWriteVisitor(WriteHandlingMethodVisitor<T>& v) const override { v.VisitNop(); }
 };
 template <typename T>
@@ -79,7 +79,7 @@ class DirectHandlingMethod : public ReadHandlingMethod<T>, public WriteHandlingM
 {
 public:
   DirectHandlingMethod(T* addr, u32 mask) : addr_(addr), mask_(mask) {}
-  virtual ~DirectHandlingMethod() {}
+  virtual ~DirectHandlingMethod() = default;
   void AcceptReadVisitor(ReadHandlingMethodVisitor<T>& v) const override
   {
     v.VisitDirect(addr_, mask_);
@@ -132,7 +132,7 @@ public:
   {
   }
 
-  virtual ~ComplexHandlingMethod() {}
+  virtual ~ComplexHandlingMethod() = default;
   void AcceptReadVisitor(ReadHandlingMethodVisitor<T>& v) const override
   {
     v.VisitComplex(&read_lambda_);
@@ -304,6 +304,8 @@ void ReadHandler<T>::ResetMethod(ReadHandlingMethod<T>* method)
 
   struct FuncCreatorVisitor : public ReadHandlingMethodVisitor<T>
   {
+    virtual ~FuncCreatorVisitor() = default;
+
     std::function<T(u32)> ret;
 
     void VisitConstant(T value) override
@@ -356,6 +358,8 @@ void WriteHandler<T>::ResetMethod(WriteHandlingMethod<T>* method)
 
   struct FuncCreatorVisitor : public WriteHandlingMethodVisitor<T>
   {
+    virtual ~FuncCreatorVisitor() = default;
+
     std::function<void(u32, T)> ret;
 
     void VisitNop() override
diff --git a/Source/Core/Core/HW/Memmap.cpp b/Source/Core/Core/HW/Memmap.cpp
index 9be01f9612..ac69e4cd6c 100644
--- a/Source/Core/Core/HW/Memmap.cpp
+++ b/Source/Core/Core/HW/Memmap.cpp
@@ -99,7 +99,7 @@ struct PhysicalMemoryRegion
   u8** out_pointer;
   u32 physical_address;
   u32 size;
-  enum
+  enum : u32
   {
     ALWAYS = 0,
     FAKE_VMEM = 1,
diff --git a/Source/Core/Core/IOS/ES/ES.cpp b/Source/Core/Core/IOS/ES/ES.cpp
index 430045705a..6023325681 100644
--- a/Source/Core/Core/IOS/ES/ES.cpp
+++ b/Source/Core/Core/IOS/ES/ES.cpp
@@ -328,7 +328,7 @@ void ES::DoState(PointerWrap& p)
   }
 }
 
-ES::ContextArray::iterator ES::FindActiveContext(u32 fd)
+ES::ContextArray::iterator ES::FindActiveContext(s32 fd)
 {
   return std::find_if(m_contexts.begin(), m_contexts.end(),
                       [fd](const auto& context) { return context.ipc_fd == fd && context.active; });
diff --git a/Source/Core/Core/IOS/ES/ES.h b/Source/Core/Core/IOS/ES/ES.h
index 1deb3919d7..b56ac57b69 100644
--- a/Source/Core/Core/IOS/ES/ES.h
+++ b/Source/Core/Core/IOS/ES/ES.h
@@ -94,7 +94,7 @@ public:
     TitleExportContext title_export;
     bool active = false;
     // We use this to associate an IPC fd with an ES context.
-    u32 ipc_fd = -1;
+    s32 ipc_fd = -1;
   };
 
   // Title management
@@ -277,7 +277,7 @@ private:
   IPCCommandResult DIGetTMDSize(const IOCtlVRequest& request);
   IPCCommandResult DIGetTMD(const IOCtlVRequest& request);
 
-  ContextArray::iterator FindActiveContext(u32 fd);
+  ContextArray::iterator FindActiveContext(s32 fd);
   ContextArray::iterator FindInactiveContext();
 
   bool LaunchIOS(u64 ios_title_id);
diff --git a/Source/Core/Core/IOS/IOS.h b/Source/Core/Core/IOS/IOS.h
index 32bcdc1694..6c49a70ec4 100644
--- a/Source/Core/Core/IOS/IOS.h
+++ b/Source/Core/Core/IOS/IOS.h
@@ -14,6 +14,7 @@
 
 #include "Common/CommonTypes.h"
 #include "Core/CoreTiming.h"
+#include "Core/HW/Memmap.h"
 #include "Core/HW/SystemTimers.h"
 #include "Core/IOS/IOSC.h"
 
@@ -82,6 +83,12 @@ enum ProcessId : u32
   PID_UNKNOWN = 19,
 };
 
+template <typename T>
+void WriteReturnValue(T value, u32 address)
+{
+  Memory::Write_U32(static_cast<u32>(value), address);
+}
+
 // HLE for the IOS kernel: IPC, device management, syscalls, and Dolphin-specific, IOS-wide calls.
 class Kernel
 {
diff --git a/Source/Core/Core/IOS/Network/IP/Top.cpp b/Source/Core/Core/IOS/Network/IP/Top.cpp
index cd25283e1a..b11800e12d 100644
--- a/Source/Core/Core/IOS/Network/IP/Top.cpp
+++ b/Source/Core/Core/IOS/Network/IP/Top.cpp
@@ -76,6 +76,11 @@ NetIPTop::~NetIPTop()
 #endif
 }
 
+static constexpr u32 inet_addr(u8 a, u8 b, u8 c, u8 d)
+{
+  return (static_cast<u32>(a) << 24) | (static_cast<u32>(b) << 16) | (static_cast<u32>(c) << 8) | d;
+}
+
 static int inet_pton(const char* src, unsigned char* dst)
 {
   int saw_digit, octets;
@@ -431,7 +436,7 @@ IPCCommandResult NetIPTop::HandleGetHostIDRequest(const IOCtlRequest& request)
 
 #ifdef _WIN32
   DWORD forwardTableSize, ipTableSize, result;
-  DWORD ifIndex = -1;
+  NET_IFINDEX ifIndex = NET_IFINDEX_UNSPECIFIED;
   std::unique_ptr<MIB_IPFORWARDTABLE> forwardTable;
   std::unique_ptr<MIB_IPADDRTABLE> ipTable;
 
@@ -462,13 +467,14 @@ IPCCommandResult NetIPTop::HandleGetHostIDRequest(const IOCtlRequest& request)
       }
     }
 
-    if (result == NO_ERROR || ifIndex != -1)
+    if (result == NO_ERROR || ifIndex != NET_IFINDEX_UNSPECIFIED)
       break;
 
     result = GetIpForwardTable(forwardTable.get(), &forwardTableSize, FALSE);
   }
 
-  if (ifIndex != -1 && GetIpAddrTable(ipTable.get(), &ipTableSize, FALSE) == NO_ERROR)
+  if (ifIndex != NET_IFINDEX_UNSPECIFIED &&
+      GetIpAddrTable(ipTable.get(), &ipTableSize, FALSE) == NO_ERROR)
   {
     for (DWORD i = 0; i < ipTable->dwNumEntries; ++i)
     {
@@ -817,9 +823,9 @@ IPCCommandResult NetIPTop::HandleGetInterfaceOptRequest(const IOCtlVRequest& req
 
   case 0x4003:  // ip addr table
     Memory::Write_U32(0xC, request.io_vectors[1].address);
-    Memory::Write_U32(10 << 24 | 1 << 8 | 30, request.io_vectors[0].address);
-    Memory::Write_U32(255 << 24 | 255 << 16 | 255 << 8 | 0, request.io_vectors[0].address + 4);
-    Memory::Write_U32(10 << 24 | 0 << 16 | 255 << 8 | 255, request.io_vectors[0].address + 8);
+    Memory::Write_U32(inet_addr(10, 0, 1, 30), request.io_vectors[0].address);
+    Memory::Write_U32(inet_addr(255, 255, 255, 0), request.io_vectors[0].address + 4);
+    Memory::Write_U32(inet_addr(10, 0, 255, 255), request.io_vectors[0].address + 8);
     break;
 
   case 0x4005:  // hardcoded value
diff --git a/Source/Core/Core/IOS/Network/KD/NWC24Config.h b/Source/Core/Core/IOS/Network/KD/NWC24Config.h
index 8aa07fc979..f25fb7b5fb 100644
--- a/Source/Core/Core/IOS/Network/KD/NWC24Config.h
+++ b/Source/Core/Core/IOS/Network/KD/NWC24Config.h
@@ -13,7 +13,7 @@ namespace HLE
 {
 namespace NWC24
 {
-enum ErrorCode : int
+enum ErrorCode : s32
 {
   WC24_OK = 0,
   WC24_ERR_FATAL = -1,
diff --git a/Source/Core/Core/IOS/Network/KD/NetKDRequest.cpp b/Source/Core/Core/IOS/Network/KD/NetKDRequest.cpp
index 48c9e27da0..cbcf245fe9 100644
--- a/Source/Core/Core/IOS/Network/KD/NetKDRequest.cpp
+++ b/Source/Core/Core/IOS/Network/KD/NetKDRequest.cpp
@@ -41,7 +41,7 @@ IPCCommandResult NetKDRequest::IOCtl(const IOCtlRequest& request)
   case IOCTL_NWC24_SUSPEND_SCHEDULAR:
     // NWC24iResumeForCloseLib  from NWC24SuspendScheduler (Input: none, Output: 32 bytes)
     INFO_LOG(IOS_WC24, "NET_KD_REQ: IOCTL_NWC24_SUSPEND_SCHEDULAR - NI");
-    Memory::Write_U32(0, request.buffer_out);  // no error
+    WriteReturnValue(0, request.buffer_out);  // no error
     break;
 
   case IOCTL_NWC24_EXEC_TRY_SUSPEND_SCHEDULAR:  // NWC24iResumeForCloseLib
@@ -50,11 +50,11 @@ IPCCommandResult NetKDRequest::IOCtl(const IOCtlRequest& request)
 
   case IOCTL_NWC24_EXEC_RESUME_SCHEDULAR:  // NWC24iResumeForCloseLib
     INFO_LOG(IOS_WC24, "NET_KD_REQ: IOCTL_NWC24_EXEC_RESUME_SCHEDULAR - NI");
-    Memory::Write_U32(0, request.buffer_out);  // no error
+    WriteReturnValue(0, request.buffer_out);  // no error
     break;
 
   case IOCTL_NWC24_STARTUP_SOCKET:  // NWC24iStartupSocket
-    Memory::Write_U32(0, request.buffer_out);
+    WriteReturnValue(0, request.buffer_out);
     Memory::Write_U32(0, request.buffer_out + 4);
     return_value = 0;
     INFO_LOG(IOS_WC24, "NET_KD_REQ: IOCTL_NWC24_STARTUP_SOCKET - NI");
@@ -74,7 +74,7 @@ IPCCommandResult NetKDRequest::IOCtl(const IOCtlRequest& request)
 
   case IOCTL_NWC24_REQUEST_REGISTER_USER_ID:
     INFO_LOG(IOS_WC24, "NET_KD_REQ: IOCTL_NWC24_REQUEST_REGISTER_USER_ID");
-    Memory::Write_U32(0, request.buffer_out);
+    WriteReturnValue(0, request.buffer_out);
     Memory::Write_U32(0, request.buffer_out + 4);
     break;
 
@@ -110,20 +110,20 @@ IPCCommandResult NetKDRequest::IOCtl(const IOCtlRequest& request)
         config.SetCreationStage(NWC24::NWC24Config::NWC24_IDCS_GENERATED);
         config.WriteConfig();
 
-        Memory::Write_U32(ret, request.buffer_out);
+        WriteReturnValue(ret, request.buffer_out);
       }
       else
       {
-        Memory::Write_U32(NWC24::WC24_ERR_FATAL, request.buffer_out);
+        WriteReturnValue(NWC24::WC24_ERR_FATAL, request.buffer_out);
       }
     }
     else if (config.CreationStage() == NWC24::NWC24Config::NWC24_IDCS_GENERATED)
     {
-      Memory::Write_U32(NWC24::WC24_ERR_ID_GENERATED, request.buffer_out);
+      WriteReturnValue(NWC24::WC24_ERR_ID_GENERATED, request.buffer_out);
     }
     else if (config.CreationStage() == NWC24::NWC24Config::NWC24_IDCS_REGISTERED)
     {
-      Memory::Write_U32(NWC24::WC24_ERR_ID_REGISTERED, request.buffer_out);
+      WriteReturnValue(NWC24::WC24_ERR_ID_REGISTERED, request.buffer_out);
     }
     Memory::Write_U64(config.Id(), request.buffer_out + 4);
     Memory::Write_U32(config.CreationStage(), request.buffer_out + 0xC);
diff --git a/Source/Core/Core/IOS/Network/SSL.cpp b/Source/Core/Core/IOS/Network/SSL.cpp
index ef826a7a58..925ab34f56 100644
--- a/Source/Core/Core/IOS/Network/SSL.cpp
+++ b/Source/Core/Core/IOS/Network/SSL.cpp
@@ -221,12 +221,12 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
       mbedtls_ssl_set_hostname(&ssl->ctx, ssl->hostname.c_str());
 
       ssl->active = true;
-      Memory::Write_U32(freeSSL, BufferIn);
+      WriteReturnValue(freeSSL, BufferIn);
     }
     else
     {
     _SSL_NEW_ERROR:
-      Memory::Write_U32(SSL_ERR_FAILED, BufferIn);
+      WriteReturnValue(SSL_ERR_FAILED, BufferIn);
     }
 
     INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_NEW (%d, %s) "
@@ -260,11 +260,11 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
 
       ssl->active = false;
 
-      Memory::Write_U32(SSL_OK, BufferIn);
+      WriteReturnValue(SSL_OK, BufferIn);
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
     }
     INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_SHUTDOWN "
                       "BufferIn: (%08x, %i), BufferIn2: (%08x, %i), "
@@ -298,19 +298,19 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
 
       if (ret)
       {
-        Memory::Write_U32(SSL_ERR_FAILED, BufferIn);
+        WriteReturnValue(SSL_ERR_FAILED, BufferIn);
       }
       else
       {
         mbedtls_ssl_conf_ca_chain(&ssl->config, &ssl->cacert, nullptr);
-        Memory::Write_U32(SSL_OK, BufferIn);
+        WriteReturnValue(SSL_OK, BufferIn);
       }
 
       INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_SETROOTCA = %d", ret);
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
     }
     break;
   }
@@ -339,19 +339,19 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
       {
         mbedtls_x509_crt_free(&ssl->clicert);
         mbedtls_pk_free(&ssl->pk);
-        Memory::Write_U32(SSL_ERR_FAILED, BufferIn);
+        WriteReturnValue(SSL_ERR_FAILED, BufferIn);
       }
       else
       {
         mbedtls_ssl_conf_own_cert(&ssl->config, &ssl->clicert, &ssl->pk);
-        Memory::Write_U32(SSL_OK, BufferIn);
+        WriteReturnValue(SSL_OK, BufferIn);
       }
 
       INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_SETBUILTINCLIENTCERT = (%d, %d)", ret, pk_ret);
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
       INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_SETBUILTINCLIENTCERT invalid sslID = %d", sslID);
     }
     break;
@@ -373,11 +373,11 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
       mbedtls_pk_free(&ssl->pk);
 
       mbedtls_ssl_conf_own_cert(&ssl->config, nullptr, nullptr);
-      Memory::Write_U32(SSL_OK, BufferIn);
+      WriteReturnValue(SSL_OK, BufferIn);
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
       INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_SETBUILTINCLIENTCERT invalid sslID = %d", sslID);
     }
     break;
@@ -395,18 +395,18 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
       if (ret)
       {
         mbedtls_x509_crt_free(&ssl->clicert);
-        Memory::Write_U32(SSL_ERR_FAILED, BufferIn);
+        WriteReturnValue(SSL_ERR_FAILED, BufferIn);
       }
       else
       {
         mbedtls_ssl_conf_ca_chain(&ssl->config, &ssl->cacert, nullptr);
-        Memory::Write_U32(SSL_OK, BufferIn);
+        WriteReturnValue(SSL_OK, BufferIn);
       }
       INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_SETBUILTINROOTCA = %d", ret);
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
     }
     INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_SETBUILTINROOTCA "
                       "BufferIn: (%08x, %i), BufferIn2: (%08x, %i), "
@@ -428,11 +428,11 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
       ssl->hostfd = sm.GetHostSocket(ssl->sockfd);
       INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_CONNECT socket = %d", ssl->sockfd);
       mbedtls_ssl_set_bio(&ssl->ctx, &ssl->hostfd, mbedtls_net_send, mbedtls_net_recv, nullptr);
-      Memory::Write_U32(SSL_OK, BufferIn);
+      WriteReturnValue(SSL_OK, BufferIn);
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
     }
     INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_CONNECT "
                       "BufferIn: (%08x, %i), BufferIn2: (%08x, %i), "
@@ -453,7 +453,7 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
     }
     break;
   }
@@ -468,7 +468,7 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
     }
     INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_WRITE "
                       "BufferIn: (%08x, %i), BufferIn2: (%08x, %i), "
@@ -491,7 +491,7 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
     }
 
     INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_READ(%d)"
@@ -507,11 +507,11 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
     int sslID = Memory::Read_U32(BufferOut) - 1;
     if (SSLID_VALID(sslID))
     {
-      Memory::Write_U32(SSL_OK, BufferIn);
+      WriteReturnValue(SSL_OK, BufferIn);
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
     }
     INFO_LOG(IOS_SSL, "IOCTLV_NET_SSL_SETROOTCADEFAULT "
                       "BufferIn: (%08x, %i), BufferIn2: (%08x, %i), "
@@ -533,11 +533,11 @@ IPCCommandResult NetSSL::IOCtlV(const IOCtlVRequest& request)
     int sslID = Memory::Read_U32(BufferOut) - 1;
     if (SSLID_VALID(sslID))
     {
-      Memory::Write_U32(SSL_OK, BufferIn);
+      WriteReturnValue(SSL_OK, BufferIn);
     }
     else
     {
-      Memory::Write_U32(SSL_ERR_ID, BufferIn);
+      WriteReturnValue(SSL_ERR_ID, BufferIn);
     }
     break;
   }
diff --git a/Source/Core/Core/IOS/Network/SSL.h b/Source/Core/Core/IOS/Network/SSL.h
index c1253e8189..a8a8d55bd2 100644
--- a/Source/Core/Core/IOS/Network/SSL.h
+++ b/Source/Core/Core/IOS/Network/SSL.h
@@ -32,7 +32,7 @@ namespace HLE
 #define SSLID_VALID(x)                                                                             \
   (x >= 0 && x < NET_SSL_MAXINSTANCES && ::IOS::HLE::Device::NetSSL::_SSL[x].active)
 
-enum ssl_err_t
+enum ssl_err_t : s32
 {
   SSL_OK = 0,
   SSL_ERR_FAILED = -1,
diff --git a/Source/Core/Core/IOS/Network/Socket.cpp b/Source/Core/Core/IOS/Network/Socket.cpp
index b5968568a1..ce79f8dfcb 100644
--- a/Source/Core/Core/IOS/Network/Socket.cpp
+++ b/Source/Core/Core/IOS/Network/Socket.cpp
@@ -335,15 +335,15 @@ void WiiSocket::Update(bool read, bool write, bool except)
             switch (ret)
             {
             case 0:
-              Memory::Write_U32(SSL_OK, BufferIn);
+              WriteReturnValue(SSL_OK, BufferIn);
               break;
             case MBEDTLS_ERR_SSL_WANT_READ:
-              Memory::Write_U32(SSL_ERR_RAGAIN, BufferIn);
+              WriteReturnValue(SSL_ERR_RAGAIN, BufferIn);
               if (!nonBlock)
                 ReturnValue = SSL_ERR_RAGAIN;
               break;
             case MBEDTLS_ERR_SSL_WANT_WRITE:
-              Memory::Write_U32(SSL_ERR_WAGAIN, BufferIn);
+              WriteReturnValue(SSL_ERR_WAGAIN, BufferIn);
               if (!nonBlock)
                 ReturnValue = SSL_ERR_WAGAIN;
               break;
@@ -366,13 +366,13 @@ void WiiSocket::Update(bool read, bool write, bool except)
               else
                 res = SSL_ERR_FAILED;
 
-              Memory::Write_U32(res, BufferIn);
+              WriteReturnValue(res, BufferIn);
               if (!nonBlock)
                 ReturnValue = res;
               break;
             }
             default:
-              Memory::Write_U32(SSL_ERR_FAILED, BufferIn);
+              WriteReturnValue(SSL_ERR_FAILED, BufferIn);
               break;
             }
 
@@ -412,24 +412,24 @@ void WiiSocket::Update(bool read, bool write, bool except)
             if (ret >= 0)
             {
               // Return bytes written or SSL_ERR_ZERO if none
-              Memory::Write_U32((ret == 0) ? SSL_ERR_ZERO : ret, BufferIn);
+              WriteReturnValue((ret == 0) ? SSL_ERR_ZERO : ret, BufferIn);
             }
             else
             {
               switch (ret)
               {
               case MBEDTLS_ERR_SSL_WANT_READ:
-                Memory::Write_U32(SSL_ERR_RAGAIN, BufferIn);
+                WriteReturnValue(SSL_ERR_RAGAIN, BufferIn);
                 if (!nonBlock)
                   ReturnValue = SSL_ERR_RAGAIN;
                 break;
               case MBEDTLS_ERR_SSL_WANT_WRITE:
-                Memory::Write_U32(SSL_ERR_WAGAIN, BufferIn);
+                WriteReturnValue(SSL_ERR_WAGAIN, BufferIn);
                 if (!nonBlock)
                   ReturnValue = SSL_ERR_WAGAIN;
                 break;
               default:
-                Memory::Write_U32(SSL_ERR_FAILED, BufferIn);
+                WriteReturnValue(SSL_ERR_FAILED, BufferIn);
                 break;
               }
             }
@@ -450,24 +450,24 @@ void WiiSocket::Update(bool read, bool write, bool except)
             if (ret >= 0)
             {
               // Return bytes read or SSL_ERR_ZERO if none
-              Memory::Write_U32((ret == 0) ? SSL_ERR_ZERO : ret, BufferIn);
+              WriteReturnValue((ret == 0) ? SSL_ERR_ZERO : ret, BufferIn);
             }
             else
             {
               switch (ret)
               {
               case MBEDTLS_ERR_SSL_WANT_READ:
-                Memory::Write_U32(SSL_ERR_RAGAIN, BufferIn);
+                WriteReturnValue(SSL_ERR_RAGAIN, BufferIn);
                 if (!nonBlock)
                   ReturnValue = SSL_ERR_RAGAIN;
                 break;
               case MBEDTLS_ERR_SSL_WANT_WRITE:
-                Memory::Write_U32(SSL_ERR_WAGAIN, BufferIn);
+                WriteReturnValue(SSL_ERR_WAGAIN, BufferIn);
                 if (!nonBlock)
                   ReturnValue = SSL_ERR_WAGAIN;
                 break;
               default:
-                Memory::Write_U32(SSL_ERR_FAILED, BufferIn);
+                WriteReturnValue(SSL_ERR_FAILED, BufferIn);
                 break;
               }
             }
@@ -479,7 +479,7 @@ void WiiSocket::Update(bool read, bool write, bool except)
         }
         else
         {
-          Memory::Write_U32(SSL_ERR_ID, BufferIn);
+          WriteReturnValue(SSL_ERR_ID, BufferIn);
         }
       }
       else
diff --git a/Source/Core/Core/IOS/SDIO/SDIOSlot0.cpp b/Source/Core/Core/IOS/SDIO/SDIOSlot0.cpp
index 3884baefdb..14a739e601 100644
--- a/Source/Core/Core/IOS/SDIO/SDIOSlot0.cpp
+++ b/Source/Core/Core/IOS/SDIO/SDIOSlot0.cpp
@@ -134,7 +134,7 @@ IPCCommandResult SDIOSlot0::IOCtlV(const IOCtlVRequest& request)
   return GetDefaultReply(IPC_SUCCESS);
 }
 
-u32 SDIOSlot0::ExecuteCommand(const Request& request, u32 _BufferIn, u32 _BufferInSize,
+s32 SDIOSlot0::ExecuteCommand(const Request& request, u32 _BufferIn, u32 _BufferInSize,
                               u32 _rwBuffer, u32 _rwBufferSize, u32 _BufferOut, u32 _BufferOutSize)
 {
   // The game will send us a SendCMD with this information. To be able to read and write
@@ -164,7 +164,7 @@ u32 SDIOSlot0::ExecuteCommand(const Request& request, u32 _BufferIn, u32 _Buffer
 
   // Note: req.addr is the virtual address of _rwBuffer
 
-  u32 ret = RET_OK;
+  s32 ret = RET_OK;
 
   switch (req.command)
   {
diff --git a/Source/Core/Core/IOS/SDIO/SDIOSlot0.h b/Source/Core/Core/IOS/SDIO/SDIOSlot0.h
index 55bfabf8da..5e69389b30 100644
--- a/Source/Core/Core/IOS/SDIO/SDIOSlot0.h
+++ b/Source/Core/Core/IOS/SDIO/SDIOSlot0.h
@@ -128,7 +128,7 @@ private:
 
   IPCCommandResult SendCommand(const IOCtlVRequest& request);
 
-  u32 ExecuteCommand(const Request& request, u32 BufferIn, u32 BufferInSize, u32 BufferIn2,
+  s32 ExecuteCommand(const Request& request, u32 BufferIn, u32 BufferInSize, u32 BufferIn2,
                      u32 BufferInSize2, u32 _BufferOut, u32 BufferOutSize);
   void OpenInternal();
 
diff --git a/Source/Core/Core/IOS/USB/Bluetooth/BTReal.cpp b/Source/Core/Core/IOS/USB/Bluetooth/BTReal.cpp
index caf3136ff4..d3aa66fc7c 100644
--- a/Source/Core/Core/IOS/USB/Bluetooth/BTReal.cpp
+++ b/Source/Core/Core/IOS/USB/Bluetooth/BTReal.cpp
@@ -533,7 +533,7 @@ void BluetoothReal::LoadLinkKeys()
     std::reverse(address.begin(), address.end());
 
     const std::string& key_string = pair.substr(index + 1);
-    linkkey_t key;
+    linkkey_t key{};
     size_t pos = 0;
     for (size_t i = 0; i < key_string.length(); i = i + 2)
     {
diff --git a/Source/Core/Core/IOS/USB/USBV4.cpp b/Source/Core/Core/IOS/USB/USBV4.cpp
index c2b9825cd6..3d963c9598 100644
--- a/Source/Core/Core/IOS/USB/USBV4.cpp
+++ b/Source/Core/Core/IOS/USB/USBV4.cpp
@@ -49,7 +49,7 @@ struct HIDRequest
 };
 #pragma pack(pop)
 
-V4CtrlMessage::V4CtrlMessage(Kernel& ios, const IOCtlRequest& ioctl) : CtrlMessage(ios, ioctl, -1)
+V4CtrlMessage::V4CtrlMessage(Kernel& ios, const IOCtlRequest& ioctl) : CtrlMessage(ios, ioctl, 0)
 {
   HIDRequest hid_request;
   Memory::CopyFromEmu(&hid_request, ioctl.buffer_in, sizeof(hid_request));
@@ -65,7 +65,7 @@ V4CtrlMessage::V4CtrlMessage(Kernel& ios, const IOCtlRequest& ioctl) : CtrlMessa
 // (US for the language and replacing non-ASCII characters with '?'),
 // we can simply submit it as a usual control request.
 V4GetUSStringMessage::V4GetUSStringMessage(Kernel& ios, const IOCtlRequest& ioctl)
-    : CtrlMessage(ios, ioctl, -1)
+    : CtrlMessage(ios, ioctl, 0)
 {
   HIDRequest hid_request;
   Memory::CopyFromEmu(&hid_request, ioctl.buffer_in, sizeof(hid_request));
@@ -87,7 +87,7 @@ void V4GetUSStringMessage::OnTransferComplete(s32 return_value) const
   TransferCommand::OnTransferComplete(return_value);
 }
 
-V4IntrMessage::V4IntrMessage(Kernel& ios, const IOCtlRequest& ioctl) : IntrMessage(ios, ioctl, -1)
+V4IntrMessage::V4IntrMessage(Kernel& ios, const IOCtlRequest& ioctl) : IntrMessage(ios, ioctl, 0)
 {
   HIDRequest hid_request;
   Memory::CopyFromEmu(&hid_request, ioctl.buffer_in, sizeof(hid_request));
diff --git a/Source/Core/Core/IOS/WFS/WFSI.cpp b/Source/Core/Core/IOS/WFS/WFSI.cpp
index a5464151b6..34e4d4e8b7 100644
--- a/Source/Core/Core/IOS/WFS/WFSI.cpp
+++ b/Source/Core/Core/IOS/WFS/WFSI.cpp
@@ -86,7 +86,7 @@ WFSI::WFSI(Kernel& ios, const std::string& device_name) : Device(ios, device_nam
 
 IPCCommandResult WFSI::IOCtl(const IOCtlRequest& request)
 {
-  u32 return_error_code = IPC_SUCCESS;
+  s32 return_error_code = IPC_SUCCESS;
 
   switch (request.request)
   {
diff --git a/Source/Core/Core/NetPlayServer.cpp b/Source/Core/Core/NetPlayServer.cpp
index 3b0112772a..1e86cf0e2d 100644
--- a/Source/Core/Core/NetPlayServer.cpp
+++ b/Source/Core/Core/NetPlayServer.cpp
@@ -367,7 +367,7 @@ unsigned int NetPlayServer::OnDisconnect(const Client& player)
         sf::Packet spac;
         spac << (MessageId)NP_MSG_DISABLE_GAME;
         // this thread doesn't need players lock
-        SendToClients(spac, -1);
+        SendToClients(spac, static_cast<PlayerId>(-1));
         break;
       }
     }
diff --git a/Source/Core/Core/PowerPC/Interpreter/Interpreter_Integer.cpp b/Source/Core/Core/PowerPC/Interpreter/Interpreter_Integer.cpp
index 480ee662da..65b8547b98 100644
--- a/Source/Core/Core/PowerPC/Interpreter/Interpreter_Integer.cpp
+++ b/Source/Core/Core/PowerPC/Interpreter/Interpreter_Integer.cpp
@@ -495,7 +495,7 @@ void Interpreter::divwx(UGeckoInstruction inst)
     }
 
     if (((u32)a & 0x80000000) && b == 0)
-      rGPR[inst.RD] = -1;
+      rGPR[inst.RD] = UINT32_MAX;
     else
       rGPR[inst.RD] = 0;
   }
diff --git a/Source/Core/Core/PowerPC/Jit64/Jit.h b/Source/Core/Core/PowerPC/Jit64/Jit.h
index 4fe96f5bfc..97ca0af716 100644
--- a/Source/Core/Core/PowerPC/Jit64/Jit.h
+++ b/Source/Core/Core/PowerPC/Jit64/Jit.h
@@ -87,7 +87,7 @@ public:
   // Use to extract bytes from a register using the regcache. offset is in bytes.
   Gen::OpArg ExtractFromReg(int reg, int offset);
   void AndWithMask(Gen::X64Reg reg, u32 mask);
-  bool CheckMergedBranch(int crf);
+  bool CheckMergedBranch(u32 crf);
   void DoMergedBranch();
   void DoMergedBranchCondition();
   void DoMergedBranchImmediate(s64 val);
diff --git a/Source/Core/Core/PowerPC/Jit64/JitRegCache.cpp b/Source/Core/Core/PowerPC/Jit64/JitRegCache.cpp
index 601bf42248..e9db74a0ad 100644
--- a/Source/Core/Core/PowerPC/Jit64/JitRegCache.cpp
+++ b/Source/Core/Core/PowerPC/Jit64/JitRegCache.cpp
@@ -30,7 +30,7 @@ void RegCache::Start()
     xreg.free = true;
     xreg.dirty = false;
     xreg.locked = false;
-    xreg.ppcReg = INVALID_REG;
+    xreg.ppcReg = static_cast<size_t>(INVALID_REG);
   }
   for (size_t i = 0; i < m_regs.size(); i++)
   {
@@ -63,7 +63,7 @@ void RegCache::DiscardRegContentsIfCached(size_t preg)
     X64Reg xr = m_regs[preg].location.GetSimpleReg();
     m_xregs[xr].free = true;
     m_xregs[xr].dirty = false;
-    m_xregs[xr].ppcReg = INVALID_REG;
+    m_xregs[xr].ppcReg = static_cast<size_t>(INVALID_REG);
     m_regs[preg].away = false;
     m_regs[preg].location = GetDefaultLocation(preg);
   }
@@ -216,7 +216,7 @@ void RegCache::StoreFromRegister(size_t i, FlushMode mode)
       if (mode == FlushMode::All)
       {
         m_xregs[xr].free = true;
-        m_xregs[xr].ppcReg = INVALID_REG;
+        m_xregs[xr].ppcReg = static_cast<size_t>(INVALID_REG);
         m_xregs[xr].dirty = false;
       }
     }
diff --git a/Source/Core/Core/PowerPC/Jit64/Jit_FloatingPoint.cpp b/Source/Core/Core/PowerPC/Jit64/Jit_FloatingPoint.cpp
index 63ac8ff7d5..12da80f64a 100644
--- a/Source/Core/Core/PowerPC/Jit64/Jit_FloatingPoint.cpp
+++ b/Source/Core/Core/PowerPC/Jit64/Jit_FloatingPoint.cpp
@@ -486,7 +486,7 @@ void Jit64::FloatCompare(UGeckoInstruction inst, bool upper)
   // bool ordered = !!(inst.SUBOP10 & 32);
   int a = inst.FA;
   int b = inst.FB;
-  int crf = inst.CRFD;
+  u32 crf = inst.CRFD;
   int output[4] = {CR_SO, CR_EQ, CR_GT, CR_LT};
 
   // Merge neighboring fcmp and cror (the primary use of cror).
diff --git a/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp b/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp
index 5f25fd5d22..2ff5e1bffe 100644
--- a/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp
+++ b/Source/Core/Core/PowerPC/Jit64/Jit_Integer.cpp
@@ -339,7 +339,7 @@ void Jit64::reg_imm(UGeckoInstruction inst)
   }
 }
 
-bool Jit64::CheckMergedBranch(int crf)
+bool Jit64::CheckMergedBranch(u32 crf)
 {
   if (!analyzer.HasOption(PPCAnalyst::PPCAnalyzer::OPTION_BRANCH_MERGE))
     return false;
@@ -473,7 +473,7 @@ void Jit64::cmpXX(UGeckoInstruction inst)
   JITDISABLE(bJITIntegerOff);
   int a = inst.RA;
   int b = inst.RB;
-  int crf = inst.CRFD;
+  u32 crf = inst.CRFD;
   bool merge_branch = CheckMergedBranch(crf);
 
   OpArg comparand;
diff --git a/Source/Core/Core/PowerPC/Jit64/Jit_LoadStore.cpp b/Source/Core/Core/PowerPC/Jit64/Jit_LoadStore.cpp
index 1d34bf4796..fc6e1f262a 100644
--- a/Source/Core/Core/PowerPC/Jit64/Jit_LoadStore.cpp
+++ b/Source/Core/Core/PowerPC/Jit64/Jit_LoadStore.cpp
@@ -202,7 +202,7 @@ void Jit64::lXXx(UGeckoInstruction inst)
       // If we're using reg+reg mode and b is an immediate, pretend we're using constant offset mode
       bool use_constant_offset = inst.OPCD != 31 || gpr.R(b).IsImm();
 
-      s32 offset;
+      s32 offset = 0;
       if (use_constant_offset)
         offset = inst.OPCD == 31 ? gpr.R(b).SImm32() : (s32)inst.SIMM_16;
       // Depending on whether we have an immediate and/or update, find the optimum way to calculate
diff --git a/Source/Core/Core/PowerPC/PPCAnalyst.cpp b/Source/Core/Core/PowerPC/PPCAnalyst.cpp
index 733bf6d3b1..c34cfd72fc 100644
--- a/Source/Core/Core/PowerPC/PPCAnalyst.cpp
+++ b/Source/Core/Core/PowerPC/PPCAnalyst.cpp
@@ -730,8 +730,8 @@ u32 PPCAnalyzer::Analyze(u32 address, CodeBlock* block, CodeBuffer* buffer, u32
     code[i].opinfo = opinfo;
     code[i].address = address;
     code[i].inst = inst;
-    code[i].branchTo = -1;
-    code[i].branchToIndex = -1;
+    code[i].branchTo = UINT32_MAX;
+    code[i].branchToIndex = UINT32_MAX;
     code[i].skip = false;
     block->m_stats->numCycles += opinfo->numCycles;
     block->m_physical_addresses.insert(result.physical_address);
diff --git a/Source/Core/Core/PowerPC/PowerPC.h b/Source/Core/Core/PowerPC/PowerPC.h
index 1ca6e6aa61..9e53c239b9 100644
--- a/Source/Core/Core/PowerPC/PowerPC.h
+++ b/Source/Core/Core/PowerPC/PowerPC.h
@@ -296,7 +296,7 @@ constexpr int BAT_INDEX_SHIFT = 17;
 constexpr u32 BAT_PAGE_SIZE = 1 << BAT_INDEX_SHIFT;
 constexpr u32 BAT_MAPPED_BIT = 0x1;
 constexpr u32 BAT_PHYSICAL_BIT = 0x2;
-constexpr u32 BAT_RESULT_MASK = ~0x3;
+constexpr u32 BAT_RESULT_MASK = UINT32_C(~0x3);
 using BatTable = std::array<u32, 1 << (32 - BAT_INDEX_SHIFT)>;  // 128 KB
 extern BatTable ibat_table;
 extern BatTable dbat_table;
diff --git a/Source/Core/DiscIO/CISOBlob.h b/Source/Core/DiscIO/CISOBlob.h
index b674dedc18..a1c8c97b40 100644
--- a/Source/Core/DiscIO/CISOBlob.h
+++ b/Source/Core/DiscIO/CISOBlob.h
@@ -48,7 +48,7 @@ private:
   CISOFileReader(File::IOFile file);
 
   typedef u16 MapType;
-  static const MapType UNUSED_BLOCK_ID = -1;
+  static const MapType UNUSED_BLOCK_ID = UINT16_MAX;
 
   File::IOFile m_file;
   u64 m_size;
diff --git a/Source/Core/DiscIO/VolumeDirectory.cpp b/Source/Core/DiscIO/VolumeDirectory.cpp
index ed965983e6..f6f603d8ff 100644
--- a/Source/Core/DiscIO/VolumeDirectory.cpp
+++ b/Source/Core/DiscIO/VolumeDirectory.cpp
@@ -35,7 +35,7 @@ const size_t VolumeDirectory::MAX_ID_LENGTH;
 
 VolumeDirectory::VolumeDirectory(const std::string& directory, bool is_wii,
                                  const std::string& apploader, const std::string& dol)
-    : m_data_start_address(-1), m_disk_header(DISKHEADERINFO_ADDRESS),
+    : m_data_start_address(UINT64_MAX), m_disk_header(DISKHEADERINFO_ADDRESS),
       m_disk_header_info(std::make_unique<SDiskHeaderInfo>()), m_fst_address(0), m_dol_address(0)
 {
   m_root_directory = ExtractDirectoryName(directory);
diff --git a/Source/Core/DiscIO/VolumeWii.cpp b/Source/Core/DiscIO/VolumeWii.cpp
index f928bbcdf3..4b6ef56539 100644
--- a/Source/Core/DiscIO/VolumeWii.cpp
+++ b/Source/Core/DiscIO/VolumeWii.cpp
@@ -32,7 +32,8 @@ namespace DiscIO
 constexpr u64 PARTITION_DATA_OFFSET = 0x20000;
 
 VolumeWii::VolumeWii(std::unique_ptr<BlobReader> reader)
-    : m_pReader(std::move(reader)), m_game_partition(PARTITION_NONE), m_last_decrypted_block(-1)
+    : m_pReader(std::move(reader)), m_game_partition(PARTITION_NONE),
+      m_last_decrypted_block(UINT64_MAX)
 {
   _assert_(m_pReader);
 
diff --git a/Source/Core/DolphinWX/Debugger/CodeWindowFunctions.cpp b/Source/Core/DolphinWX/Debugger/CodeWindowFunctions.cpp
index 2452e85b38..2a536c95e6 100644
--- a/Source/Core/DolphinWX/Debugger/CodeWindowFunctions.cpp
+++ b/Source/Core/DolphinWX/Debugger/CodeWindowFunctions.cpp
@@ -146,11 +146,12 @@ void CCodeWindow::OnProfilerMenu(wxCommandEvent& event)
       File::CreateFullPath(filename);
       Profiler::WriteProfileResults(filename);
 
-      wxFileType* filetype = nullptr;
-      if (!(filetype = wxTheMimeTypesManager->GetFileTypeFromExtension("txt")))
+      wxFileType* filetype = wxTheMimeTypesManager->GetFileTypeFromExtension("txt");
+      if (!filetype)
       {
         // From extension failed, trying with MIME type now
-        if (!(filetype = wxTheMimeTypesManager->GetFileTypeFromMimeType("text/plain")))
+        filetype = wxTheMimeTypesManager->GetFileTypeFromMimeType("text/plain");
+        if (!filetype)
           // MIME type failed, aborting mission
           break;
       }
diff --git a/Source/Core/DolphinWX/Debugger/DSPDebugWindow.cpp b/Source/Core/DolphinWX/Debugger/DSPDebugWindow.cpp
index 922fd3c0c7..8c4be0c3f4 100644
--- a/Source/Core/DolphinWX/Debugger/DSPDebugWindow.cpp
+++ b/Source/Core/DolphinWX/Debugger/DSPDebugWindow.cpp
@@ -32,7 +32,7 @@ static DSPDebuggerLLE* m_DebuggerFrame = nullptr;
 
 DSPDebuggerLLE::DSPDebuggerLLE(wxWindow* parent, wxWindowID id)
     : wxPanel(parent, id, wxDefaultPosition, wxDefaultSize, wxTAB_TRAVERSAL, _("DSP LLE Debugger")),
-      m_CachedStepCounter(-1), m_toolbar_item_size(FromDIP(wxSize(16, 16)))
+      m_CachedStepCounter(UINT64_MAX), m_toolbar_item_size(FromDIP(wxSize(16, 16)))
 {
   Bind(wxEVT_MENU, &DSPDebuggerLLE::OnChangeState, this, ID_RUNTOOL, ID_SHOWPCTOOL);
 
diff --git a/Source/Core/DolphinWX/Debugger/MemoryCheckDlg.cpp b/Source/Core/DolphinWX/Debugger/MemoryCheckDlg.cpp
index 6d6b1450e7..ac870c8804 100644
--- a/Source/Core/DolphinWX/Debugger/MemoryCheckDlg.cpp
+++ b/Source/Core/DolphinWX/Debugger/MemoryCheckDlg.cpp
@@ -154,7 +154,7 @@ void MemoryCheckDlg::OnOK(wxCommandEvent& event)
   bool Log = m_radioLog->GetValue() || m_radioBreakLog->GetValue();
   bool Break = m_radioBreak->GetValue() || m_radioBreakLog->GetValue();
 
-  u32 StartAddress, EndAddress;
+  u32 StartAddress = UINT32_MAX, EndAddress = 0;
   bool EndAddressOK =
       EndAddressString.Len() && AsciiToHex(WxStrToStr(EndAddressString), EndAddress);
 
diff --git a/Source/Core/DolphinWX/VideoConfigDiag.cpp b/Source/Core/DolphinWX/VideoConfigDiag.cpp
index 65dc4c3603..22490e4ad5 100644
--- a/Source/Core/DolphinWX/VideoConfigDiag.cpp
+++ b/Source/Core/DolphinWX/VideoConfigDiag.cpp
@@ -1322,11 +1322,11 @@ void VideoConfigDiag::PopulatePostProcessingShaders()
 
 void VideoConfigDiag::PopulateAAList()
 {
-  const std::vector<int>& aa_modes = vconfig.backend_info.AAModes;
+  const auto& aa_modes = vconfig.backend_info.AAModes;
   const bool supports_ssaa = vconfig.backend_info.bSupportsSSAA;
   m_msaa_modes = 0;
 
-  for (int mode : aa_modes)
+  for (auto mode : aa_modes)
   {
     if (mode == 1)
     {
@@ -1342,7 +1342,7 @@ void VideoConfigDiag::PopulateAAList()
 
   if (supports_ssaa)
   {
-    for (int mode : aa_modes)
+    for (auto mode : aa_modes)
     {
       if (mode != 1)
         choice_aamode->AppendString(std::to_string(mode) + "x SSAA");
diff --git a/Source/Core/InputCommon/GCAdapter.cpp b/Source/Core/InputCommon/GCAdapter.cpp
index 2cb7819d9d..a422e2635e 100644
--- a/Source/Core/InputCommon/GCAdapter.cpp
+++ b/Source/Core/InputCommon/GCAdapter.cpp
@@ -266,27 +266,26 @@ static bool CheckDeviceAccess(libusb_device* device)
       }
       return false;
     }
-    else if ((ret = libusb_kernel_driver_active(s_handle, 0)) == 1)
+    else
     {
-      if ((ret = libusb_detach_kernel_driver(s_handle, 0)) && ret != LIBUSB_ERROR_NOT_SUPPORTED)
+      ret = libusb_kernel_driver_active(s_handle, 0);
+      if (ret == 1)
       {
-        ERROR_LOG(SERIALINTERFACE, "libusb_detach_kernel_driver failed with error: %d", ret);
+        ret = libusb_detach_kernel_driver(s_handle, 0);
+        if (ret != 0 && ret != LIBUSB_ERROR_NOT_SUPPORTED)
+          ERROR_LOG(SERIALINTERFACE, "libusb_detach_kernel_driver failed with error: %d", ret);
       }
     }
     // this split is needed so that we don't avoid claiming the interface when
     // detaching the kernel driver is successful
     if (ret != 0 && ret != LIBUSB_ERROR_NOT_SUPPORTED)
-    {
       return false;
-    }
-    else if ((ret = libusb_claim_interface(s_handle, 0)))
-    {
+
+    ret = libusb_claim_interface(s_handle, 0);
+    if (ret)
       ERROR_LOG(SERIALINTERFACE, "libusb_claim_interface failed with error: %d", ret);
-    }
     else
-    {
       return true;
-    }
   }
   return false;
 }
diff --git a/Source/Core/VideoBackends/D3D/D3DBase.cpp b/Source/Core/VideoBackends/D3D/D3DBase.cpp
index 8000f15a31..327fece109 100644
--- a/Source/Core/VideoBackends/D3D/D3DBase.cpp
+++ b/Source/Core/VideoBackends/D3D/D3DBase.cpp
@@ -240,12 +240,12 @@ D3D_FEATURE_LEVEL GetFeatureLevel(IDXGIAdapter* adapter)
   return feat_level;
 }
 
-static bool SupportsS3TCTextures(ID3D11Device* device)
+static bool SupportsS3TCTextures(ID3D11Device* dev)
 {
   UINT bc1_support, bc2_support, bc3_support;
-  if (FAILED(device->CheckFormatSupport(DXGI_FORMAT_BC1_UNORM, &bc1_support)) ||
-      FAILED(device->CheckFormatSupport(DXGI_FORMAT_BC2_UNORM, &bc2_support)) ||
-      FAILED(device->CheckFormatSupport(DXGI_FORMAT_BC3_UNORM, &bc3_support)))
+  if (FAILED(dev->CheckFormatSupport(DXGI_FORMAT_BC1_UNORM, &bc1_support)) ||
+      FAILED(dev->CheckFormatSupport(DXGI_FORMAT_BC2_UNORM, &bc2_support)) ||
+      FAILED(dev->CheckFormatSupport(DXGI_FORMAT_BC3_UNORM, &bc3_support)))
   {
     return false;
   }
@@ -320,7 +320,7 @@ HRESULT Create(HWND wnd)
         return desc.Count == g_Config.iMultisamples;
       }) == aa_modes.end())
   {
-    Config::SetCurrent(Config::GFX_MSAA, 1);
+    Config::SetCurrent(Config::GFX_MSAA, UINT32_C(1));
     UpdateActiveConfig();
   }
 
diff --git a/Source/Core/VideoBackends/OGL/Render.cpp b/Source/Core/VideoBackends/OGL/Render.cpp
index ebec5e98a9..ec709c152b 100644
--- a/Source/Core/VideoBackends/OGL/Render.cpp
+++ b/Source/Core/VideoBackends/OGL/Render.cpp
@@ -63,7 +63,7 @@ static std::unique_ptr<RasterFont> s_raster_font;
 
 // 1 for no MSAA. Use s_MSAASamples > 1 to check for MSAA.
 static int s_MSAASamples = 1;
-static int s_last_multisamples = 1;
+static u32 s_last_multisamples = 1;
 static bool s_last_stereo_mode = false;
 static bool s_last_xfb_mode = false;
 
@@ -519,7 +519,7 @@ Renderer::Renderer()
       {
         // GLES 3.1 can't support stereo rendering and MSAA
         OSD::AddMessage("MSAA Stereo rendering isn't supported by your GPU.", 10000);
-        Config::SetCurrent(Config::GFX_MSAA, 1);
+        Config::SetCurrent(Config::GFX_MSAA, UINT32_C(1));
       }
     }
     else
diff --git a/Source/Core/VideoBackends/OGL/TextureCache.cpp b/Source/Core/VideoBackends/OGL/TextureCache.cpp
index 2031d7e220..169dec0bc5 100644
--- a/Source/Core/VideoBackends/OGL/TextureCache.cpp
+++ b/Source/Core/VideoBackends/OGL/TextureCache.cpp
@@ -370,9 +370,9 @@ TextureCache::TextureCache()
 {
   CompileShaders();
 
-  s_ActiveTexture = -1;
+  s_ActiveTexture = UINT32_MAX;
   for (auto& gtex : s_Textures)
-    gtex = -1;
+    gtex = UINT32_MAX;
 
   if (g_ActiveConfig.backend_info.bSupportsPaletteConversion)
   {
@@ -519,8 +519,8 @@ bool TextureCache::CompileShaders()
 
   s_ColorMatrixUniform = glGetUniformLocation(s_ColorMatrixProgram.glprogid, "colmat");
   s_DepthMatrixUniform = glGetUniformLocation(s_DepthMatrixProgram.glprogid, "colmat");
-  s_ColorCbufid = -1;
-  s_DepthCbufid = -1;
+  s_ColorCbufid = UINT32_MAX;
+  s_DepthCbufid = UINT32_MAX;
 
   s_ColorCopyPositionUniform = glGetUniformLocation(s_ColorCopyProgram.glprogid, "copy_position");
   s_ColorMatrixPositionUniform =
diff --git a/Source/Core/VideoBackends/Vulkan/Renderer.cpp b/Source/Core/VideoBackends/Vulkan/Renderer.cpp
index 94087bdc1f..81bd7671cd 100644
--- a/Source/Core/VideoBackends/Vulkan/Renderer.cpp
+++ b/Source/Core/VideoBackends/Vulkan/Renderer.cpp
@@ -1106,7 +1106,7 @@ void Renderer::CheckForSurfaceChange()
 void Renderer::CheckForConfigChanges()
 {
   // Save the video config so we can compare against to determine which settings have changed.
-  int old_multisamples = g_ActiveConfig.iMultisamples;
+  u32 old_multisamples = g_ActiveConfig.iMultisamples;
   int old_anisotropy = g_ActiveConfig.iMaxAnisotropy;
   int old_stereo_mode = g_ActiveConfig.iStereoMode;
   int old_aspect_ratio = g_ActiveConfig.iAspectRatio;
diff --git a/Source/Core/VideoCommon/AVIDump.cpp b/Source/Core/VideoCommon/AVIDump.cpp
index dc4e806f6a..6a7590f034 100644
--- a/Source/Core/VideoCommon/AVIDump.cpp
+++ b/Source/Core/VideoCommon/AVIDump.cpp
@@ -159,8 +159,9 @@ bool AVIDump::CreateVideoFile()
 
   const AVCodec* codec = nullptr;
 
-  if (!(codec = avcodec_find_encoder(codec_id)) ||
-      !(s_codec_context = avcodec_alloc_context3(codec)))
+  codec = avcodec_find_encoder(codec_id);
+  s_codec_context = avcodec_alloc_context3(codec);
+  if (!codec || !s_codec_context)
   {
     ERROR_LOG(VIDEO, "Could not find encoder or allocate codec context");
     return false;
@@ -203,8 +204,8 @@ bool AVIDump::CreateVideoFile()
     return false;
 #endif
 
-  if (!(s_stream = avformat_new_stream(s_format_context, codec)) ||
-      !AVStreamCopyContext(s_stream, s_codec_context))
+  s_stream = avformat_new_stream(s_format_context, codec);
+  if (!s_stream || !AVStreamCopyContext(s_stream, s_codec_context))
   {
     ERROR_LOG(VIDEO, "Could not create stream");
     return false;
@@ -299,9 +300,10 @@ void AVIDump::AddFrame(const u8* data, int width, int height, int stride, const
   s_src_frame->height = s_height;
 
   // Convert image from {BGR24, RGBA} to desired pixel format
-  if ((s_sws_context =
-           sws_getCachedContext(s_sws_context, width, height, s_pix_fmt, s_width, s_height,
-                                s_codec_context->pix_fmt, SWS_BICUBIC, nullptr, nullptr, nullptr)))
+  s_sws_context =
+      sws_getCachedContext(s_sws_context, width, height, s_pix_fmt, s_width, s_height,
+                           s_codec_context->pix_fmt, SWS_BICUBIC, nullptr, nullptr, nullptr);
+  if (s_sws_context)
   {
     sws_scale(s_sws_context, s_src_frame->data, s_src_frame->linesize, 0, height,
               s_scaled_frame->data, s_scaled_frame->linesize);
diff --git a/Source/Core/VideoCommon/Fifo.cpp b/Source/Core/VideoCommon/Fifo.cpp
index 377d7d5010..cedbea5432 100644
--- a/Source/Core/VideoCommon/Fifo.cpp
+++ b/Source/Core/VideoCommon/Fifo.cpp
@@ -353,7 +353,7 @@ void RunGpuLoop()
                 DataReader(s_video_buffer_read_ptr, write_ptr), &cyclesExecuted, false);
 
             Common::AtomicStore(fifo.CPReadPointer, readPtr);
-            Common::AtomicAdd(fifo.CPReadWriteDistance, -32);
+            Common::AtomicAdd(fifo.CPReadWriteDistance, static_cast<u32>(-32));
             if ((write_ptr - s_video_buffer_read_ptr) == 0)
               Common::AtomicStore(fifo.SafeCPReadPointer, fifo.CPReadPointer);
 
diff --git a/Source/Core/VideoCommon/ImageWrite.cpp b/Source/Core/VideoCommon/ImageWrite.cpp
index 6156ca2cb1..e7930a18c6 100644
--- a/Source/Core/VideoCommon/ImageWrite.cpp
+++ b/Source/Core/VideoCommon/ImageWrite.cpp
@@ -21,6 +21,11 @@ bool SaveData(const std::string& filename, const std::string& data)
   return true;
 }
 
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4611)
+#endif
+
 /*
 TextureToPng
 
@@ -31,20 +36,16 @@ row_stride: Determines the amount of bytes per row of pixels.
 bool TextureToPng(const u8* data, int row_stride, const std::string& filename, int width,
                   int height, bool saveAlpha)
 {
-  bool success = false;
-
   if (!data)
     return false;
 
+  bool success = false;
   char title[] = "Dolphin Screenshot";
   char title_key[] = "Title";
   png_structp png_ptr = nullptr;
   png_infop info_ptr = nullptr;
   std::vector<u8> buffer;
 
-  if (!saveAlpha)
-    buffer.resize(width * 4);
-
   // Open file for writing (binary mode)
   File::IOFile fp(filename, "wb");
   if (!fp.IsOpen())
@@ -70,13 +71,22 @@ bool TextureToPng(const u8* data, int row_stride, const std::string& filename, i
     goto finalise;
   }
 
-  // Setup Exception handling
+  // Classical libpng error handling uses longjmp to do C-style unwind.
+  // Modern libpng does support a user callback, but it's required to operate
+  // in the same way (just gives a chance to do stuff before the longjmp).
+  // Instead of futzing with it, we use gotos specifically so the compiler
+  // will still generate proper destructor calls for us (hopefully).
+  // We also do not use any local variables outside the region longjmp may
+  // have been called from if they were modified inside that region (they
+  // would need to be volatile).
   if (setjmp(png_jmpbuf(png_ptr)))
   {
     PanicAlert("Screenshot failed: Error during PNG creation");
     goto finalise;
   }
 
+  // Begin region which may call longjmp
+
   png_init_io(png_ptr, fp.GetHandle());
 
   // Write header (8 bit color depth)
@@ -91,6 +101,9 @@ bool TextureToPng(const u8* data, int row_stride, const std::string& filename, i
 
   png_write_info(png_ptr, info_ptr);
 
+  if (!saveAlpha)
+    buffer.resize(width * 4);
+
   // Write image data
   for (auto y = 0; y < height; ++y)
   {
@@ -114,6 +127,8 @@ bool TextureToPng(const u8* data, int row_stride, const std::string& filename, i
   // End write
   png_write_end(png_ptr, nullptr);
 
+  // End region which may call longjmp
+
   success = true;
 
 finalise:
@@ -124,3 +139,7 @@ finalise:
 
   return success;
 }
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
diff --git a/Source/Core/VideoCommon/IndexGenerator.cpp b/Source/Core/VideoCommon/IndexGenerator.cpp
index 79dbc92597..74f6a8a728 100644
--- a/Source/Core/VideoCommon/IndexGenerator.cpp
+++ b/Source/Core/VideoCommon/IndexGenerator.cpp
@@ -16,7 +16,7 @@ u16* IndexGenerator::index_buffer_current;
 u16* IndexGenerator::BASEIptr;
 u32 IndexGenerator::base_index;
 
-static const u16 s_primitive_restart = -1;
+static const u16 s_primitive_restart = UINT16_MAX;
 
 static u16* (*primitive_table[8])(u16*, u32, u32);
 
diff --git a/Source/Core/VideoCommon/TextureCacheBase.cpp b/Source/Core/VideoCommon/TextureCacheBase.cpp
index 613f2dfed9..72978f6752 100644
--- a/Source/Core/VideoCommon/TextureCacheBase.cpp
+++ b/Source/Core/VideoCommon/TextureCacheBase.cpp
@@ -994,7 +994,7 @@ void TextureCacheBase::CopyRenderTargetToTexture(u32 dstAddr, unsigned int dstFo
   float* const ColorMask = colmat + 20;
   ColorMask[0] = ColorMask[1] = ColorMask[2] = ColorMask[3] = 255.0f;
   ColorMask[4] = ColorMask[5] = ColorMask[6] = ColorMask[7] = 1.0f / 255.0f;
-  unsigned int cbufid = -1;
+  unsigned int cbufid = UINT_MAX;
   u32 srcFormat = bpmem.zcontrol.pixel_format;
   bool efbHasAlpha = srcFormat == PEControl::RGBA6_Z24;
 
diff --git a/Source/Core/VideoCommon/VertexLoaderBase.h b/Source/Core/VideoCommon/VertexLoaderBase.h
index a895300466..509ccb4310 100644
--- a/Source/Core/VideoCommon/VertexLoaderBase.h
+++ b/Source/Core/VideoCommon/VertexLoaderBase.h
@@ -36,7 +36,7 @@ public:
 private:
   size_t CalculateHash() const
   {
-    size_t h = -1;
+    size_t h = SIZE_MAX;
 
     for (auto word : vid)
     {
diff --git a/Source/Core/VideoCommon/VideoConfig.h b/Source/Core/VideoCommon/VideoConfig.h
index 707afae84c..03d102eb62 100644
--- a/Source/Core/VideoCommon/VideoConfig.h
+++ b/Source/Core/VideoCommon/VideoConfig.h
@@ -70,7 +70,7 @@ struct VideoConfig final
   bool bShaderCache;
 
   // Enhancements
-  int iMultisamples;
+  u32 iMultisamples;
   bool bSSAA;
   int iEFBScale;
   bool bForceFiltering;
@@ -167,7 +167,7 @@ struct VideoConfig final
     APIType api_type;
 
     std::vector<std::string> Adapters;  // for D3D
-    std::vector<int> AAModes;
+    std::vector<u32> AAModes;
 
     // TODO: merge AdapterName and Adapters array
     std::string AdapterName;  // for OpenGL
diff --git a/Source/VSProps/Base.props b/Source/VSProps/Base.props
index 4fe3f0e379..31336f3c07 100644
--- a/Source/VSProps/Base.props
+++ b/Source/VSProps/Base.props
@@ -76,7 +76,7 @@
       higher declaration can be contained to just the XAudio2/XInput related code.
       -->
       <PreprocessorDefinitions>_WIN32_WINNT=0x0602;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <WarningLevel>Level3</WarningLevel>
+      <WarningLevel>Level4</WarningLevel>
       <TreatWarningAsError>true</TreatWarningAsError>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <RuntimeTypeInfo>false</RuntimeTypeInfo>
@@ -95,13 +95,36 @@
       <DebugInformationFormat>OldStyle</DebugInformationFormat>
       <DiagnosticsFormat>Caret</DiagnosticsFormat>
       <!--
-      4996 is for GetVersionEx being marked as depreciated - which is idiotic and there's
-        not much else we can do since many externals use it. The bad part is that there doesn't
-        seem to be a way to only ignore the specific instance we don't care about...
-      4351 squashes a warning telling us the compiler is behaving as expected (instead of old,
-        broken behavior).
+      4996  is for GetVersionEx being marked as deprecated - which is idiotic and there's not much
+                else we can do since many externals use it. The bad part is that there doesn't
+                seem to be a way to only ignore the specific instance we don't care about...
+      4351  new behavior: elements of array 'array' will be default initialized
       -->
       <DisableSpecificWarnings>4996;4351</DisableSpecificWarnings>
+      <!-- Warnings one may want to ignore when using Level4.
+      4201  nonstandard extension used : nameless struct/union
+      4127  conditional expression is constant
+      4100  'identifier' : unreferenced formal parameter
+      4244  'conversion' conversion from 'type1' to 'type2', possible loss of data
+                Level4 warns if type1==int and there is narrowing
+      4121  'symbol' : alignment of a member was sensitive to packing
+      4324  Padding was added at the end of a structure because you specified a __declspec(align) value.
+      4714  function 'function' marked as __forceinline not inlined
+      -->
+      <DisableSpecificWarnings>4201;4127;4100;4244;4121;4324;4714;%(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <!-- Level4 warnings which should eventually be enabled
+      4245  'conversion' : conversion from 'type1' to 'type2', signed/unsigned mismatch
+                Currently jits use some annoying code patterns which makes this common
+      -->
+      <DisableSpecificWarnings>4245;%(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <!-- Enable some off-by-default warnings
+      4263  Non-virtual member function hides base class virtual function
+      4265  Class has virtual functions, but destructor is not virtual
+      4946  Reinterpret cast between related types
+      -->
+      <!-- Externals are currently not compatible with this. Can still uncomment locally.
+      <AdditionalOptions>/we4263 /we4265 /we4946 %(AdditionalOptions)</AdditionalOptions>
+      -->
     </ClCompile>
     <!--ClCompile Debug-->
     <ClCompile Condition="'$(Configuration)'=='Debug'">