Having trouble with a cumulative update from October

Question

My Windows finally went and updated to 25H2 this afternoon, and while it was smooth, I've hit a bump.
After going to my Windows Update and checking for further updates, which all went well, there's one that seemingly refuses to stay put. The update in question is 2025-10 Cumulative Update for .NET Framework 3.5 and 4.8.1 for Windows 11, version 25H2 for x64 (KB5066128); whenever I download and install it, it's in my update history as "successfully installed" with today's date (the 25th of February).
However, if I either restart my device, shut it down and start it up again, or even just go back to the main Windows Update page and click "check for updates" again, it'll download and install again. I've tried three times now but I daren't try again in case it's just adding itself constantly.
I've also tried running the Windows Update troubleshooter, but that hasn't helped at all.

Has anyone else had this problem with this cumulative update or others like it, and will I be able to download and install future cumulative updates? Does the fact it shows up in my update as successfully installed mean that it has indeed installed?

I'd appreciate any help with this!

EDIT 27/2: Thank you so much for all of your help, Dave. I've finally found-out what was causing the cumulative update (KB5066128) to continuously download and install if I checked for updates; apparently I just had to download and install the 2026-01 .NET Framework Preview Update (KB5074828). Now if I go back and select "check for updates", the cumulative update no longer downloads and installs again.

This problem has now been solved!

Answer 1

In this case, I suggest you use the system file checker to repair possible corrupted or missing system files.

1. Open Start and type cmd, right-click on "Command Prompt", and select "Run as administrator".
2. Run the following commands at the Command Prompt one at a time:

dism.exe /online /cleanup-image /scanhealth
dism.exe /online /cleanup-image /restorehealth
dism.exe /online /cleanup-image /startcomponentcleanup
sfc /scannow

Note: Pay close attention to the results of the commands. This will help you determine whether the procedure was completed successfully or if there was a problem. If you get any errors, let me know the error message that was displayed.

3. Then restart (not shutdown) your PC and see if the problem stops.

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If the problem persists, try this:

1. Press "Windows + R", type optionalfeatures.exe, and press Enter;
2. Uncheck ".NET Framework 3.5 (includes .NET 2.0 and 3.0)" and ".NET Framework 4.8 Advanced Services."
3. Click OK to let it apply, and restart (not shutdown) your PC.
4. After the restart, go back and re-check both boxes.

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If the problem persists, please let me know, and I will provide another method.

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Feel free to ask any questions you may have.

Answer 2

Thanks for the clarification.

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A moderator has undeleted your messages.

Based on the OS Build you provided, your system is installing updates. Therefore, I don't think future updates will be affected.

However, I will share a procedure that may help you with this problem.

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Rename the software distribution folders as instructed below. This should reset the Windows Update cache.

1. Open Start and type cmd, right-click on "Command Prompt", and select "Run as administrator".
2. Run the following commands at the Command Prompt one at a time:

net stop bits
net stop wuauserv
net stop cryptsvc
ren %systemroot%\softwaredistribution softwaredistribution.bak
ren %systemroot%\system32\catroot2 catroot2.bak
net start bits
net start wuauserv
net start cryptsvc

3. After all these commands are completed, close the Command Prompt window, restart (not shutdown) your computer.

You may need to "install" this update one last time, or it will simply disappear because it's already installed.

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If the problem persists, please let me know.

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Feel free to ask any questions you may have.

Answer 3

Hi, and thanks for a quick response, Dave! I already replied to your post as a comment to your reply but I'm not sure if you had been notified, so I'll put what I said there here.

I have Avira Antivirus and Malwarebytes, but I didn't think they'd have had any effect on this.

Do I need the cumulative update that I mentioned, the one ending in KB5066128? Since it's an October update and we're now nearly in March, I would assume that following cumulative updates would have superseded it. If I go and look in my Quality Updates through Windows Update, it's there and it says it was successfully installed, but the problem persists as mentioned in my original post. It will download and install again if I go and click "check for updates", or if I shut down and startup my laptop.

Answer 4

Hi. I'm David, and I'm happy to help you.

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Please clarify the following:

Do you have a third-party antivirus installed? If yes, which one?

Also. Let me know the current "OS Build" of your Windows 11.

• Press "Windows + R", type winver, and click OK.

If you prefer, share a screenshot. Use the shortcut "Windows + Shift + S" to use the screenshot tool.

Be sure to censor your email address if it appears. The Microsoft Q&A is public.

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I await your reply.