diff --git a/reactos/subsystems/win32/win32k/ntuser/vis.c b/reactos/subsystems/win32/win32k/ntuser/vis.c
index d89a1348097..50a1e2cf9ae 100644
--- a/reactos/subsystems/win32/win32k/ntuser/vis.c
+++ b/reactos/subsystems/win32/win32k/ntuser/vis.c
@@ -69,7 +69,7 @@ VIS_ComputeVisibleRegion(
    while (CurrentWindow)
    {
       CurrentWnd = CurrentWindow->Wnd;
-      if (!(CurrentWnd->Style & WS_VISIBLE))
+      if (!(CurrentWnd) || !(CurrentWnd->Style & WS_VISIBLE))
       {
          NtGdiDeleteObject(VisRgn);
          return NULL;