Update KB5120998, build 26200.9278 (28.08.2026) broke taskbar Icons and can't be uninstalled

Mop Toddel 0 Zuverlässigkeitspunkte
2026-08-31T14:12:36.5266667+00:00

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Since installing Windows 11 preview update KB5120998 on August 28, 2026, on Windows 11 25H2, build 26200.9278, many pinned taskbar icons in my main user profile are displayed only as grey boxes. The applications themselves still work and launch normally. A second user profile on the same PC displays the same applications and taskbar icons correctly.

The issue started immediately after KB5120998 was installed. My previously configured desktop wallpaper was also reset/removed after the update.

I have already tried the following:

  • Resetting Microsoft.Windows.ShellExperienceHost and Microsoft.Windows.StartMenuExperienceHost using Reset-AppxPackage
  • Completely resetting the pinned taskbar state, including HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Taskband
  • Deleting pinned taskbar shortcuts under %APPDATA%\Microsoft\Internet Explorer\Quick Launch\User Pinned\TaskBar
  • Deleting icon cache files under %LOCALAPPDATA%\Microsoft\Windows\Explorer
  • Deleting %LOCALAPPDATA%\IconCache.db
  • Re-registering ShellExperienceHost
  • Signing out and back in
  • Restarting Windows multiple times
  • Manually pinning affected applications again

Freshly pinned applications still show grey taskbar icons. After rebuilding the icon cache, the problem actually became worse and additional icons were affected.

I also tried to uninstall KB5120998:

  • KB5120998 does not appear as removable under Settings → Windows Update → Update history → Uninstall updates
  • “Uninstall latest quality update” from Windows Recovery Environment did not change the installed build
  • wusa.exe /uninstall /kb:5120998 reports that the update is required and cannot be uninstalled
  • DISM /Online /Remove-Package fails with error 0x800f0825
  • DISM explicitly logs: Permanent package cannot be uninstalled

The installed package is:

Package_for_RollupFix~31bf3856ad364e35~amd64~~26100.9278.1.35

Before KB5120998, the system was running build 26200.9168 and this problem did not occur.

Since a second user profile on the same Windows installation still displays taskbar icons correctly, this appears to be a KB5120998 regression affecting per-user Explorer/taskbar/icon state rather than a general application or graphics issue.

Please investigate whether this is a known regression in KB5120998 and whether a fix or Known Issue Rollback is planned.

Windows für Zuhause | Windows 11 | Windows-Update
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  1. Clary-N 16,550 Zuverlässigkeitspunkte Externe Microsoft-Mitarbeiter Moderator
    2026-09-01T07:57:53.79+00:00

    Hi Mop Toddel,

    Thank you for documenting the issue and the troubleshooting already completed. I can see that you’re using English, so I’ll continue supporting you in this language. If you’d prefer to switch to another language, just let me know.

    Since the same applications display correctly in a second user profile, this appears isolated to the original profile’s taskbar, shell, or personalization state rather than the applications themselves.

    I checked the current KB5120998 release notes. Microsoft does not currently list grey taskbar icons as a known issue, and no Known Issue Rollback or planned fix has been announced. Although the timing and wallpaper reset suggest the update may be involved, this has not been officially confirmed.

    As the next repair option, please back up important files, connect the PC to power and the internet, then:

    1. Open Settings > System > Recovery.
    2. Under Fix problems using Windows Update, select Reinstall now.
    3. Follow the prompts and restart when requested.

    This reinstalls the current Windows version, repairs system files and components, and preserves applications, files and settings.

    If Reinstall now is unavailable, I recommend using the unaffected profile temporarily and waiting for a later Windows update rather than making additional changes to the affected profile.

    I hope the repair installation helps and please let me know how it goes.

    If you have extra questions about this answer, please click "Comment".  

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