I am trying to install Windows 11, version 26H2 but getting an error code - Install error - 0x800f0831

Repair the Windows component store with DISM and SFC before retrying 26H2, because error 0x800F0831 (CBS_E_STORE_CORRUPTION) specifically indicates component-store corruption rather than a general 26H2 availability problem.^1^

1. Repair Windows components

Keep the computer connected to power and the internet. DISM normally obtains replacement files from Windows Update.

1. Open Start, type Command Prompt.
2. Right-click Command Prompt and select Run as administrator.
3. Run these commands individually, allowing each to finish:

DISM.exe /Online /Cleanup-Image /RestoreHealth
SFC.exe /Scannow

4. Confirm that DISM reports “The restore operation completed successfully.”
5. Restart the computer.
6. Open Settings → Windows Update → Check for updates, then install 26H2 again.

This is Microsoft’s documented repair sequence for 0x800F0831.^2^

Since repeated Retry attempts have already failed, do not continue retrying before completing the repair.

2. If DISM succeeds but 26H2 still fails

Run the automated update diagnostics:

1. Open Settings → System → Troubleshoot → Other troubleshooters.
2. Find Windows Update and select Run.
3. Apply any recommended correction.
4. Restart, return to Settings → Windows Update, and try the installation once more.^3^

Also disconnect nonessential USB drives, printers, docks, and other external hardware during the upgrade. Microsoft recommends removing such devices when troubleshooting Windows upgrade failures.^4^

3. If DISM fails or reports that source files could not be found

Use Windows 11’s supported non-destructive repair installation:

1. Back up important personal files.
2. Open Settings → System → Recovery.
3. Under Fix problems using Windows Update, select Reinstall now.
4. Keep the PC connected to power and the internet.
5. Restart when installation finishes.
6. Check for updates and retry 26H2.

This reinstalls the current Windows version, repairs system files and components, and preserves applications, files, and settings.^5^

If Fix problems using Windows Update is absent, it can be unavailable on managed work/school PCs or systems missing the required servicing updates. In that case, avoid manually removing component-store packages unless the exact missing KB has been identified from C:\Windows\Logs\CBS\CBS.log.

4. Confirm the result

After the update completes:

1. Press Windows key + R.
2. Enter winver.
3. Confirm that the dialog reports Version 26H2.

Windows 11 26H2 is currently available for eligible devices, and Microsoft directs users to install it through Settings → Windows Update.^6^ The displayed 0x800F0831 error is therefore handled as a local servicing/component-store failure, not proof that 26H2 is unavailable for the device.

References

1. Windows Update common errors and mitigation
2. Fix Windows Update corruptions and installation failures
3. [Windows 11](https://support.microsoft.com/windows/experience/windows-update-troubleshooter)
4. [Windows 11](https://support.microsoft.com/windows/deployment/install-upgrade/get-help-with-windows-upgrade-and-installation-errors)
5. Fix issues by reinstalling the current version of Windows | Microsoft Support
6. Windows 11, version 26H2 known issues and notifications