diff --git a/src/mzcom/stdafx.h b/src/mzcom/stdafx.h
index 478cbb029b..77990381cd 100644
--- a/src/mzcom/stdafx.h
+++ b/src/mzcom/stdafx.h
@@ -11,7 +11,7 @@
 
 #define STRICT
 #ifndef _WIN32_WINNT
-#define _WIN32_WINNT 0x0400
+#define _WIN32_WINNT 0x0501
 #endif
 #define _ATL_APARTMENT_THREADED