diff --git a/win32ss/user/ntuser/message.c b/win32ss/user/ntuser/message.c
index 79d68a184ea..ae0c0733ebe 100644
--- a/win32ss/user/ntuser/message.c
+++ b/win32ss/user/ntuser/message.c
@@ -1423,7 +1423,7 @@ UserPostMessage( HWND Wnd,
         if ( Window->state & WNDS_DESTROYED )
         {
             ERR("Attempted to post message to window %p that is being destroyed!\n", Wnd);
-            /* FIXME: Last error code? */
+            EngSetLastError(ERROR_INVALID_WINDOW_HANDLE);
             return FALSE;
         }