diff --git a/reactos/win32ss/user/ntuser/message.c b/reactos/win32ss/user/ntuser/message.c
index 8d4b346f619..caad8d54f91 100644
--- a/reactos/win32ss/user/ntuser/message.c
+++ b/reactos/win32ss/user/ntuser/message.c
@@ -2760,7 +2760,7 @@ NtUserMessageCall( HWND hWnd,
                 _SEH2_END;
             }
 
-            Ret = co_IntDoSendMessage( hWnd, Msg, wParam, lParam, &dsm );
+            Ret = co_IntDoSendMessage( hWnd, Msg, wParam, lParam, pdsm ? &dsm : NULL );
 
             if (pdsm)
             {