Windows update not working

Question

Windows update not working

Ronald Greenberg 0

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.

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3 answers

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Answer 1

Kapil Arya 37,551 Volunteer Moderator

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!

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Answer 2

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.

Ronald Greenberg 0 Reputation points

2026-04-07T12:19:27.5566667+00:00

I downloaded the ISO and when I double click, it does not say ,mount, but rather a dialogue asking me to accept and install. This seems to be different that mounting and then running setup.exe. Please advise as I do not want to make a mistake and lose programs and data. Thanks.

Answer 3

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):

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.
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.
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.
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.
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.

References:

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