diff --git a/dlls/mshtml/mshtml_private.h b/dlls/mshtml/mshtml_private.h
index 58ef4238ae5..55375d42b00 100644
--- a/dlls/mshtml/mshtml_private.h
+++ b/dlls/mshtml/mshtml_private.h
@@ -40,7 +40,7 @@
 #include "nsiface.h"
 
 #define NS_ERROR_GENERATE_FAILURE(module,code) \
-    ((nsresult) (((UINT32)(1<<31)) | ((UINT32)(module+0x45)<<16) | ((UINT32)(code))))
+    ((nsresult) (((UINT32)(1u<<31)) | ((UINT32)(module+0x45)<<16) | ((UINT32)(code))))
 
 #define NS_OK                     ((nsresult)0x00000000L)
 #define NS_ERROR_FAILURE          ((nsresult)0x80004005L)