diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6c1058059a..46ca44025b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -315,7 +315,11 @@ if(LIB_INSTALL_DIR)
 endif()
 
 if (NOT EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/framework/CMakeLists.txt")
-    message(FATAL_ERROR "${CMAKE_CURRENT_SOURCE_DIR}/framework/CMakeLists.txt not found. Run `git submodule update --init` from the source tree to fetch the submodule contents.")
+    if (EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/.git/")
+        message(FATAL_ERROR "${CMAKE_CURRENT_SOURCE_DIR}CMakeLists.txt not found (and does appear to be a git checkout). Run `git submodule update --init` from the source tree to fetch the submodule contents.")
+    else ()
+        message(FATAL_ERROR "${CMAKE_CURRENT_SOURCE_DIR}/CMakeLists.txt not found (and does not appear to be a git checkout). Please ensure you have downloaded the right archive from the release page on GitHub.")
+    endif()
 endif()
 add_subdirectory(framework)
 
diff --git a/Makefile b/Makefile
index e4d98c93aa..09c829ab5f 100644
--- a/Makefile
+++ b/Makefile
@@ -6,11 +6,16 @@ ifneq (,$(filter-out lib library/%,$(or $(MAKECMDGOALS),all)))
     ifeq (,$(wildcard framework/exported.make))
         # Use the define keyword to get a multi-line message.
         # GNU make appends ".  Stop.", so tweak the ending of our message accordingly.
-        define error_message
-$(MBEDTLS_PATH)/framework/exported.make not found.
-Run `git submodule update --init` to fetch the submodule contents.
+        ifeq (,$(wildcard .git))
+            define error_message
+${MBEDTLS_PATH}/framework/exported.make not found (and does appear to be a git checkout). Run `git submodule update --init` from the source tree to fetch the submodule contents.
 This is a fatal error
-        endef
+            endef
+        else
+            define error_message
+${MBEDTLS_PATH}/framework/exported.make not found (and does not appear to be a git checkout). Please ensure you have downloaded the right archive from the release page on GitHub.
+            endef
+        endif
         $(error $(error_message))
     endif
     include framework/exported.make