File History problems after installing KB5124008

Question

File History problems after installing KB5124008

BobH3027 110

Ran Windows Update on two sepearate Windows 11 computers that were all up to date as of Saturday morning - broke File History

Today I ran File History on 2 computers - both ran correctly. Then ran Windows Update and File History on both are now broken. File History panel pops up but will not run - says to connect a drive. (drive was connected and verified that I could read and write to it)

Reached out to support who logged on to one of the computers, but troubleshooting did not provide an answer. Later I connected a drive and configured File History on a 3rd computer - it was working. Then I ran Windows Update and it broke it.

Updated the case number and was told now by two seperate techs that it seems to be an issue with one of the updates and was passing it on to level 2 with the detailed testing notes I provided.

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Alan B 5 Reputation points

2026-09-09T08:30:26.7133333+00:00

I'm having the same issues trying to run my back up to file history on my external drive- failed, same error messages as you. Had to do a manual save to the drive. CHATGPT says likely that what you have highlighted is the problem and microsoft will pick up and solve soon.
La Ma 10 Reputation points

2026-09-10T03:41:21.8066667+00:00

I have just now encountered this same problem. I will try uninstalling the Security Update.
Ezio De Pazzi 131 Reputation points

2026-09-10T05:47:41.74+00:00

exactly what you are expericing.
dotlang 40 Reputation points

2026-09-16T16:04:04.0966667+00:00

.....
Sean Page 10 Reputation points

2026-09-17T17:46:07.8066667+00:00

Thank you so much for that information. Wish I had read it sooner. I installed a fresh Windows 10 onto a PC to give to my parents. After copying all their files and apps across, creating 2 accounts etc, I ran file history and Backup & Restore with no problems. Then (seemingly out of nowhere) file history threw this error, which doesn't even seem to be an error, just telling you that the drive isn't connected. Ended up reinstalling windows from scratch, after doing the sfc/dism/anything, even thinking that my backup drive was faulty, only to come into this same problem again, but only after installing updates. Process of elimination. Deduction, dear Watson. Currently restoring a system image and will not install patch updates afterward. To myself and my parents, having an integral file backup working is more important than a botched security fix. What annoys the most is spending so much time looking in the wrong places online for answers to this seemingly random problem, only for it to be an update bricking features. Just wish I'd seen this before doing a job twice 🤣

7 answers

Your answer

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Alan B 5 Reputation points

2026-09-09T08:30:26.7133333+00:00

I'm having the same issues trying to run my back up to file history on my external drive- failed, same error messages as you. Had to do a manual save to the drive. CHATGPT says likely that what you have highlighted is the problem and microsoft will pick up and solve soon.
La Ma 10 Reputation points

2026-09-10T03:41:21.8066667+00:00

I have just now encountered this same problem. I will try uninstalling the Security Update.
Ezio De Pazzi 131 Reputation points

2026-09-10T05:47:41.74+00:00

exactly what you are expericing.
dotlang 40 Reputation points

2026-09-16T16:04:04.0966667+00:00

.....
Sean Page 10 Reputation points

2026-09-17T17:46:07.8066667+00:00

Thank you so much for that information. Wish I had read it sooner. I installed a fresh Windows 10 onto a PC to give to my parents. After copying all their files and apps across, creating 2 accounts etc, I ran file history and Backup & Restore with no problems. Then (seemingly out of nowhere) file history threw this error, which doesn't even seem to be an error, just telling you that the drive isn't connected. Ended up reinstalling windows from scratch, after doing the sfc/dism/anything, even thinking that my backup drive was faulty, only to come into this same problem again, but only after installing updates. Process of elimination. Deduction, dear Watson. Currently restoring a system image and will not install patch updates afterward. To myself and my parents, having an integral file backup working is more important than a botched security fix. What annoys the most is spending so much time looking in the wrong places online for answers to this seemingly random problem, only for it to be an update bricking features. Just wish I'd seen this before doing a job twice 🤣

Answer 1

BobH3027 110

Resolved the issue for now by uninstalling
2026-09 Security Update (KB5124008) (26200.9445)

Did this all three computers that had the issue and it resolved the issue on all three.

La Ma 10 Reputation points

2026-09-10T11:03:37.36+00:00

For me also, uninstalling that Security Update resolved the issue. But of course, I also had to pause updates until the end of the month. I don't want Windows Update to re-install it!
BobH3027 110 Reputation points

2026-09-10T11:23:35.6933333+00:00

You can hide the update from being installed so you can still get other updates. Best method I found was using commands in the admin terminal )PowerShell).

Only caveat is that if Windows Update has already downloaded it, you need to install it, uninstall it, then run the commands to block it. Search "Block the Installation of Certain Windows Updates Using PowerShell" on the Internet.
Carl-L 21,915 Reputation points Microsoft External Staff Moderator

2026-09-10T13:44:21.6933333+00:00

Hello BobHayes-3027,

It's good to hear if you have found a way to resolve this.

If you have any other questions. Feel free to ask.
Fred Acosta 10 Reputation points

2026-09-10T15:45:10.5966667+00:00

Thank you BobHayes for posting this. I had the same exact issue and removing KB5124008 resolved it.

Much appreciated.

-Fred A.
Derek S 30 Reputation points

2026-09-10T16:44:35.2+00:00
What concerns me about the "uninstall the update" answer is that it doesn't tell us whether Microsoft has:

acknowledged the bug,

logged it,

reproduced it,

or fixed it.

It merely demonstrates a correlation:

"I removed the update and File History worked again."

That's useful information, but it's not the same as a long-term solution.
BobH3027 110 Reputation points

2026-09-10T17:15:27.69+00:00

Dereck S - I'd like to knw that as well, but as far as I know there is no feedback loop to customers to provide that information. More importantly, will it still be an issue in the next Security Update.

Like youm I'm just a user of Windows sharing the issue and what fixed it for me, and what to be aware of come the next update. I even took the time to install the update - 2026-09 Security Update (KB5124008) (26200.9445) - again on each computer to confirm it was that update that broke File History before uninstalling it to make it work again.

Good Luck
Derek S 30 Reputation points

2026-09-10T18:08:38.93+00:00

Thanks, Bob. I really appreciate you taking the time to post the issue in the first place and then doing the extra testing to confirm the behaviour after reinstalling the update.

Finding your post was actually what prompted me to investigate my own File History setup. Up until then I assumed I was dealing with a problem specific to my PC or backup drive. After working through quite a bit of troubleshooting, I'm now much less convinced that it's simply a hardware issue.

In any case, thank you again for starting the thread and sharing your findings. I'll continue following it with interest and will post back if I discover anything useful.
Derek S 30 Reputation points

2026-09-10T19:07:34.2633333+00:00
I just happened to check Windows Security and Maintenance and discovered that Windows Security and Maintenance is recording repeated crashes of FileHistory.exe:

Problem Event Name: CLR20r3

Faulting application: FileHistory.exe

Module: fhuxadapter

Exception: System.InvalidOperationException

The same crash has been recorded multiple times with the same bucket ID, which suggests a repeatable failure rather than a one-off event.

According to Copilot:

CLR20r3 is a .NET runtime crash. In plain English, it means an application encountered an unhandled exception and terminated unexpectedly.

An InvalidOperationException is essentially:
"The program attempted an operation that wasn't valid for the state it was in."

That's a software exception rather than a hardware error.

The fhuxadapter component is part of the File History user experience/UI layer rather than the actual file-copying engine.

Copilot added:
"That fits surprisingly well with your symptoms:

"Turn Off" does nothing.

"Run now" doesn't actually start a backup.

"Reconnect your drive" appears despite the drive being accessible.

New FileHistory-Engine events aren't appearing.

Those are all UI/control-plane behaviours, not disk I/O failures."
BobH3027 110 Reputation points

2026-09-10T19:51:34.87+00:00

Yes - I showed Tech Support while he was connected to my computer that clicking "Turn Off" did not do anything and clicking "Run Now" only brings up the "Reconnect your drive" message. Also - stopping the FH service, removing the FH folder on your backup drive and "Users\xxxxx\AppData\Local\Microsoft then starting FH does in fact recreate the folders abd allows you to exclude folders and other settings - just won't actually run :)

Hopefully MS will get enough complaints and fix it. What has me a little concerned is that when I reached back out to update them with the info that uninstalling the update fixed the issue they told me that there were no notes under the case number - so I do not have a high level of confidence that it actually went to level 2 for further investigation.
MollFran88 10 Reputation points

2026-09-11T05:53:16.5166667+00:00

As a very unsophisticated older user I really appreciated all the information in this thread, thank you. I uninstalled the security update and could back up onto an external hard drive again. Windows automatically reinstalling the update reproduced the problem. I don't have confidence to pause just one update so will just have to do a few "copy"s of vital files to a different drive every so often until next month. I am concerned though, as I gather the security updates are different each time so that the issues fixed in the suspect update won't be fixed in the following month if I uninstall it.

I don't know how to report it directly to Microsoft, as it looks from the above as if they've not taken anything on board yet.

Thanks guys.

Answer 2

Mike_A_P 25

Seems that Microsoft is not in any hurry to acknowledge this as a known issue for KB5124008. Does anyone have suggestions for raising awareness? FWIW I reported it on Feedback Hub (at https://aka.ms/AA13dwm5) and there was at least one other report, but can't find it any longer. Not sure how effective Feedback Hub is, but might help if people could leave more reports or upvote... Meanwhile, has anyone seen any work-arounds apart from uninstalling the update? EDIT: Just installed latest OOB update KB5129195 (26200.9457) which apparently addresses two of the three acknowledged issues with KB5124008. File History still failing with apparently the same symptoms.

JamieB 20 Reputation points

2026-09-15T22:52:05.85+00:00

I upvoted although I'm not sure how much help it will be. There is definitely an issue and just silence from Microsoft.

Obviously they would like people to move away from FileHistory but while it is still included in the Win11 features they need to make sure it works.
J L Donley 0 Reputation points

2026-09-16T14:31:36.92+00:00

I cannot turn File History back on. KB5124008 no longer on list that I can uninstall it.
BobH3027 110 Reputation points

2026-09-16T14:39:43.13+00:00

@J L Donley MS released a new Security Update yesterday but it did not include a fix for the File History issue. 2026-09 Security Update (KB5129195) (26200.9457) Remove that and FH should work.
J L Donley 0 Reputation points

2026-09-16T14:51:54.6366667+00:00

When I click on Uninstall Updates I now have a list of only 5 updates, and that is not one of them.
Mark Lovell 5 Reputation points

2026-09-19T15:57:05.81+00:00

It mentioned as a known issue in the 2026-09 Security Update (KB5124008) - see the release notes

https://support.microsoft.com/en-us/servicing/os/windows-11/2026/09/kb5124008-windows-11-24h2-25h2-security-update
Mike_A_P 25 Reputation points

2026-09-19T16:55:40.2966667+00:00

Thanks Mark - Very reassuring to see this now acknowledged!

Answer 3

Henrik Mygind 10

Any updates on this.

After installing KB5124008, i have the exact same problem with File History. And the "Reconnect the drive" message.

Have even tried with a fresh SSD drive and renaming Configuration and Data directories on the PC, then selected the new drive in File History, and it will create fresh Configuration and Data directories on both the external SSD and the PC, so it can for sure see the drive. Then Run backup and l get the same message to Reconnect the drive. So this is clearly broken !

BobH3027 110 Reputation points

2026-09-16T11:03:22.0666667+00:00

MS released a new Security Update yesterday but it did not include a fix for the File History issue.
2026-09 Security Update (KB5129195) (26200.9457)

Having removed the KB5124008 update my File History was working until the new KB5129195 udate broke it again - removing that (and blocking it or pausing updates) allows Filre History to work again - at least it does on my computers.
Henrik Mygind 10 Reputation points

2026-09-16T11:40:02.67+00:00

Yes I did also install KB5129195 but it didn't fix it. So crossing my fingers for a new fix soon
Bruin_71 10 Reputation points

2026-09-17T02:58:13.73+00:00

I experienced the same File History problem several days ago. Trouble is, when I tried to uninstall KB5124008 with "Uninstall Updates", it isn't listed. On the other hand, KB5129195, the latest Security Update, is listed (i.e., it can be uninstalled). Do any of you think that I can restore File History functionality by just uninstalling this last one (KB5129195)? Or do both security updates need to be removed?

Second question, if I leave the situation as it stands, is the next scheduled Security Update in October likely to correct the glitch?
dotlang 40 Reputation points

2026-09-17T03:40:26.41+00:00

Same problem. KB5124008 isn't listed in the Uninstall list. Note that it IS listed in the Windows Update History.
Mike_A_P 25 Reputation points

2026-09-17T07:51:30.67+00:00

Just tried rolling back from KB5129195 (Windows version 25H2 26200.9457) and that seems to get back only to version 26200.9445, so File History is still broken - however, KB5124008 then reappears in the list of updates that can be uninstalled. On doing so (oh what fun) the version rolled back to 26200.9168, and File History functionality does then seem to be restored. It has, though, started a new FileHistory folder and would not reconnect with an old, empty, and re-named FileHistory folder that had been created while File History was not working properly, under 26200.9457, so not sure if it will recognise a previous valid folder (I'd not previously been running File History on this device). Good luck.

Answer 4

Linda Rolla 5

Uninstalling those two pesky updates did the trick. File History working again.I hope Microsoft fixes this!

BobH3027 110 Reputation points

2026-09-13T22:20:57.7266667+00:00

Only need to uninstalled 2026-09 Security Update (KB5124008) (26200.9445), but Windows will reinstall it in a day or two unless you block it (it get's blocked at the KB5124008 level, not the 26200.9445 sublevel). As CrazyKats pointed out there is an update to KB5124008 but it is not GA yet - guess not until the 2nd Tues in October from what I read about how MS releases them. Guess that a fix to File History is not likely to be in the Beta update, so it could be a while. When I see an update is available (by checking the Microsoft Update Catalog) I will download it on a system I do not use File History on and test it and post an update.
MollFran88 10 Reputation points

2026-09-15T00:11:37.12+00:00

I have just installed the most recent update available, newly available today, 2026-09 Security Update (KB5129195) (26200.9457) and the external hard drive back-up inability problem still persists. As this was a second Security Update within a month, (only a week since the last one), I assume there must have been lots of bugs in last week's one.

Many of us want to backup to an external hard drive.

I have reported this on Feedback Hub also. Get a grip Microsoft!

Please return us to a fully functioning back-up situation.
BobH3027 110 Reputation points

2026-09-15T00:52:14.95+00:00

Agree - still broken. Was working before I ran the update - not working after installing it - working after I uninstalled it.

Answer 5

Carl-L 21,915 Microsoft External Staff Moderator

Hello Bob H,

Welcome to Microsoft Q&A forum.

Before we proceed, may I have a photo of the situation to check for you? Please remember to remove all personal information before posting.

Additionally, may I know if you can rollback the updates?

I'm waiting for your reply.

BobH3027 110 Reputation points

2026-09-09T13:43:43.57+00:00

Sure - here you go - tried it with two external USB drives and one internal drive, all which I have verified can be read and written to. Microsoft Tech support connected to computer and also verified drive was able to be written too as well as doing SFC and DISM commands. Then finally agreed that since File History was working be the updates (manually run prior to installing the updates) and is now not working after the updates on all three computers it is an issue with one or more of the three updates that were installed.

While that error message was being displayed I manually copied a file over to the backup drive and could also read it.

Rather than trying to blindly uninstall all three updates - what order would you suggest I try to uninstall them in?
Derek S 30 Reputation points

2026-09-10T08:34:38.77+00:00

Greetings all,
If I may just add a little more info from my perspective. I am unable to turn File History off! If I click 'Turn off' it still shows that 'File History is on", as in the photo supplied by BobHayes-3027. If I click 'Run now', that's when the message to "Reconnect your drive" appears. I am able to Stop the File History service by running services.msc, but when it is running again, nothing changes from my description above. While trying this last night, it did create the following folder structure on the backup drive: D:\File History<user_name><System_name> which contained two more sub -folders: 'Configuration' and 'Data'. In 'Configuration, there were two files: Config1.xml and Config2.xml but nothing in data. Again, it says it is turned on but if I click Run now, I get the 'reconnect drive' message.
In addition, Copilot is recommending NOT to uninstall KB5124008, with this being an important Security update, so I am reluctant to try that. Also, there is no option to stop using the currently selected drive or the option to select another drive.
Hopefully some of what I've said here may be of use in helping to diagnose this issue. I'm feeling vulnerable now with out File History running.