diff --git a/win32ss/user/ntuser/clipboard.c b/win32ss/user/ntuser/clipboard.c
index 9790b867467..2b404406cf3 100644
--- a/win32ss/user/ntuser/clipboard.c
+++ b/win32ss/user/ntuser/clipboard.c
@@ -359,6 +359,9 @@ UserClipboardRelease(PWND pWindow)
 {
     PWINSTATION_OBJECT pWinStaObj;
 
+    if (!pWindow)
+        return;
+
     pWinStaObj = IntGetWinStaForCbAccess();
     if (!pWinStaObj)
         return;