diff --git a/reactos/subsystems/win32/win32k/ntuser/window.c b/reactos/subsystems/win32/win32k/ntuser/window.c
index 5c71931c5a1..681d957acfc 100644
--- a/reactos/subsystems/win32/win32k/ntuser/window.c
+++ b/reactos/subsystems/win32/win32k/ntuser/window.c
@@ -2184,7 +2184,7 @@ CLEANUP:
        /* If the window was created, the class will be dereferenced by co_UserDestroyWindow */
        if (Window) 
             co_UserDestroyWindow(Window);
-       else
+       else if (Class)
            IntDereferenceClass(Class, pti->pDeskInfo, pti->ppi);
    }