diff --git a/library/x509_crt.c b/library/x509_crt.c
index a784e634dd..e3b30db988 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -61,9 +61,6 @@
 #if defined(MBEDTLS_HAVE_TIME)
 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
 #define WIN32_LEAN_AND_MEAN
-#ifndef _WIN32_WINNT
-#define _WIN32_WINNT 0x0600
-#endif
 #include <windows.h>
 #else
 #include <time.h>