Windows update not working

Question

I have Windows 11, Version 24H2. installed 2/23/25, OS Build 23100.6584. I have been trying to load "2025-10 Cumulative Update for Windows 11 Version 24H2 for x64-based Systems (KB5066835) (26100.6899)" and it keeps failing. I have tried to use the troubleshooter, but it just spins and never completes. I then tried to use the System - Recovery - Update Troubleshooter process, but it is greyed out and showing it is unavailable.

How do I fix Windows so it can be updated without losing any programs or data?

Thanks.

Answer 1

I would suggest going to the Recovery option in Settings > System > Recovery > Fix problems using windows update, select Reinstall now.

Then check for updates again.

Are you sure the build is 23100.6584 that doesn't seem to match a release build unless you are using an Insider Preview perhaps.

Answer 2

Hi Ronald Greenberg,

The most convenient way is to perform an In-place upgrade. Please follow this article.

Disclaimer: Let’s try performing an in-place install or in-place upgrade which will refresh your Windows files and operating system without removing files or applications. That being said, we always recommend that if you have important data, you should back it up before making large system changes. If you want to back up your data first, please do so. Once you are done backing up, you can follow the steps in the following guides: How to run In-place upgrade in Windows 11 - Microsoft Community

After doing so, your system will get 25H2 directly.

If you have further information, please feel free to let me know.

Answer 3

Hello,

Try installing the failed update KB5066835 via Update Catalog:

https://www.catalog.update.microsoft.com/Search.aspx?q=KB5066835

Let us know if this helps!

Answer 4

Hi Ronald,

Thank you for posting your question here!

Because your system is on build 23100.6584 and KB5066835 requires the 26100-servicing baseline, Windows Update cannot complete the install and the troubleshooters fail or show unavailable. To fix this without losing programs or data, download the latest Windows 11 24H2 ISO from Microsoft, double click it to mount, run setup.exe from inside Windows, choose Keep personal files and apps, and let the upgrade complete. This performs an in-place repair that realigns the servicing stack and component store. After rebooting, run Windows Update again and KB5066835 should install normally.

You can download here: Windows 11 Installation Assistant

Let me know if you need further assistance, feel free to ask me by clicking "Add Comment" or "Add Answer" if you cannot add comment so your response will be visible. Thank you and I appreciate your effort.

Best Regards,

Angelique P.

Answer 5

To repair Windows Update without losing programs or data, use an in-place upgrade/repair install of Windows 11 24H2. This keeps files and apps while replacing system components, including Windows Update.

Follow these steps (summary adapted from similar 25H2 repair guidance):

1. Create a backup and restore point
   • Back up important personal files to external storage or cloud.
   • Create a System Restore Point so changes can be rolled back if needed.
2. Download the Windows 11 ISO
   • Go to the official Windows 11 download page:
     • Under “Download Windows 11 Disk Image (ISO)”, choose “Windows 11 (multi-edition ISO for x64 devices)”.
     • Select language, then download the 64-bit ISO.
3. Start the in-place upgrade
   • After the ISO finishes downloading, double-click the ISO file to mount it.
   • In the mounted drive, run Setup.exe.
   • On the “Install Windows 11” screen:
     • Clear any checkbox like “I want to help make the installation better” if shown.
     • If prompted “Change how Windows Setup downloads updates”, choose “Not right now” so setup uses the local files.
   • Accept the license terms.
4. Choose what to keep
   • On the “Ready to install” screen, select “Change what to keep”.
   • Choose “Keep personal files and apps”. This preserves installed programs and data.
   • Confirm and click “Install”. The PC will restart several times.
5. After setup completes
   • Sign back in and open Settings → Windows Update.
   • Click “Check for updates” and install KB5066835 again.

If Windows Update still fails after the repair install, contact Microsoft Support for further investigation, as similar cases have been resolved by direct support assistance.

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References:

• Windows Update Troubleshooter
• Windows 11, version 24H2 update history
• Windows 11, version 23H2 update history
• Plethora of issues relating to windows and possibly security. - Microsoft Q&A I'm not sure where to start.
• Mijn windows updates gaan mis - Microsoft Q&A Windows 11, version 25H2
• 2025-10 Cumulative Update for Windows 11 Version 23H2 for x64-based Systems (KB5066793) Install error - 0x800f0922 - Microsoft Q&A
• windows 11version 25H2 couldn't install, error 0x80070476 - Microsoft Q&A
• Any Updates from windows 11 release preview 26220.6690 - Microsoft Q&A
• KB5066683: Setup Dynamic Update for Windows 11, version 24H2 and Windows Server 2025: September 29, 2025