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Windows 11 Alt+TAB ghost thumbnails

Ben S 0 Reputation points
2025-10-15T00:30:56.5433333+00:00

Hi, we are having an issue with our software on Windows 11 24H2 Alt+TAB function.

When users do Alt+TAB, it creates additional thumbnails in the Alt+TAB view despite our application running once in a single window. This seems to happen if the window is maximized. The Alt+TAB view eventually gets flooded with ghost thumbnails of the app and the thumbnails persist even after closing the app.

 

Our software is developed in C++17 using MFC (Microsoft Foundation Classes) and compiled in 32-bit using Visual Studio. Despite our research, we have not found a solution to this issue, which is impacting the work of thousands of journalists around the world.

Could you please help us resolve this issue?

Thanks!

Windows development | Windows API - Win32

3 answers

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  1. FlorDjam 5 Reputation points
    2025-10-17T11:13:30.6933333+00:00

    We found out the solution :

    One of our child control have the WS_EX_APPWINDOW style. We just changed the style of this control as WS_EX_TOOLWINDOW and it works.
    Thank you very much for your help.

    Edit : Unfortunatly after a system reboot the alt-tab continue to produce new windows.

    1 person found this answer helpful.
  2. Linhnguyen Hanoi 0 Reputation points
    2025-10-15T02:29:04.9833333+00:00

    I suggest you could try to use Spy++ to identify all top-level windows your app creates. And then check window styles of all visible and invisible windows.

    You should ensure all secondary windows have WS_EX_TOOLWINDOW style and only your main window has WS_EX_APPWINDOW. A tool window does not appear in the taskbar or in the dialog that appears when the user presses ALT+TAB.

  3. Omkara Varshitha Kunapalli (INFOSYS LIMITED) 1,450 Reputation points Microsoft External Staff
    2025-10-15T05:22:24.17+00:00

    Hope your doing well . Thanks for reaching out

    This is a known issue affecting some applications on Windows 11 24H2, especially those built with MFC and running in maximized mode

    .1. Check for KB5060829 Update

    • This update has been linked to Alt+Tab issues. Try uninstalling it temporarily to see if the problem resolves
      1. Avoid Maximized Window State
    • Run the app in normal (non-maximized) mode to reduce thumbnail duplication.
    • You can test this by launching the app with SW_SHOWNORMAL instead of SW_MAXIMIZE.

    3 . Force Single Thumbnail via Window Styles

    • Ensure your main window has WS_EX_APPWINDOW and WS_EX_TOOLWINDOW styles set correctly.
    • Improper use of these styles can cause multiple taskbar or Alt+Tab entries.
    1. Use SetWindowLong with GWL_EXSTYLE

    LONG exStyle = GetWindowLong(hWnd, GWL_EXSTYLE); SetWindowLong(hWnd, GWL_EXSTYLE, exStyle | WS_EX_APPWINDOW);

    This forces Windows to treat the window as a standalone app, reducing ghost entries.

    1. Try ExplorerPatcher or Third-Party Tools
    • Some developers have used ExplorerPatcher to restore classic Alt+Tab behavior, though results vary 6. Report to Microsoft
    • Since this affects many users, consider submitting a bug report via Microsoft Q&A or the Feedback Hub.

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