how to fix error message for windows update 2026-08 Security Update (KB5121003) (26200.9168)

Question

Each time I try to update 2026-08 Security Update (KB5121003) (26200.9168) it say error, retry. Is there a way to fix this.

Answer 1

Try this in order:

1. Restart the PC, then go to Settings > Windows Update and select Check for updates again.
2. Run component cleanup from an elevated Command Prompt:

      dism /online /cleanup-image /startcomponentcleanup
   

   Then restart the device and try Windows Update again.
3. If it still fails, repair the component store and system files from an elevated Command Prompt:

      DISM /ONLINE /CLEANUP-IMAGE /SCANHEALTH
      DISM /ONLINE /CLEANUP-IMAGE /CHECKHEALTH
      DISM /ONLINE /CLEANUP-IMAGE /RESTOREHEALTH
      Sfc /Scannow
   

   Restart the device after the commands finish, then try the update again.
4. If Windows Update still cannot install it, download the update manually from the Microsoft Update Catalog and install the package that matches the operating system.
5. If the update package reports that the Windows Modules Installer or servicing stack must be updated first, use Windows Update to install the required servicing update, or install the required servicing stack update for the operating system before retrying the .msu package.
6. If the issue continues after that, reinstall the current version of Windows as a repair install.

Note: DISM and SFC are repair tools, but they modify system components. Let them complete fully and restart before testing Windows Update again.

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References:

• When trying to install updates from Windows Update you might receive "Updates Failed. There were problems installing some updates, but we'll try again later" with Errors: 0x80073701, 0x800f0988
• Error 0x800f0831 when you install an update
• Error message when you install a .msu update package on a computer that is running Windows: "The Windows Modules Installer must be updated before you can install this package"
• How to fix Windows failing to update and saying Install error - 0x800f0983? - Microsoft Q&A

Answer 2

Hi Jennifer,

What is the failing error?

When does it fail, download or install?

Please file the issue in the Feedback

Hub using WIN+F.