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Latest Security Update Fails to Install

Charlie Zuck 20 Reputation points
2026-05-16T13:24:15.5666667+00:00

The 2026-05 Security Update (KB5089549) (26200.8457) failed to install numerous times. I get install error 0x800f0922.

I ran SFC /scannow, Dism /online /cleanup-image /restorehealth, and bits. Nothing has helped. Looking for help, I really don't want to reinstall Windows 11.

 

Windows for home | Windows 11 | Windows update

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AI answer

2026-05-16T13:24:25.5733333+00:00

Error 0x800f0922 with the May 2026 security update KB5089549 on Windows 11 is a known issue and is commonly caused by limited free space on the EFI System Partition (ESP), especially when there is 10 MB or less free.

To work around this without reinstalling Windows 11, use the supported registry-based mitigation for the ESP:

  1. Open Command Prompt as Administrator.
  2. Run this command exactly as shown: 
       reg add "HKLM\SYSTEM\CurrentControlSet\Control\Bfsvc" /v EspPaddingPercent /t REG_DWORD /d 0 /f
  3. Restart the device.
  4. After the restart, run Windows Update again and retry installing KB5089549.

Warning: Editing the registry incorrectly can cause system issues. Ensure the command is typed exactly and that a backup or restore point exists before making changes.

If the issue persists even after this workaround, the problem might be mitigated later via Known Issue Rollback (KIR) delivered automatically through Windows Update once available.

References:

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