Microsoft has confirmed a Windows 11 File History bug that can stop backups after the September 2026 security update, while telling users to reconnect a drive that is already working. The problem affects Windows 11 versions 24H2 and 25H2, and it is easy to miss until a file needs restoring.
Windows Latest reported that the issue began with KB5124008, released on September 8. File History can fail to recognise an external or network drive, leaving scheduled backups stalled. Microsoft’s support page describes the same symptom: File History might fail to back up or restore files, and the system may incorrectly display a “Reconnect your drive” message. Windows Latest reported the original failure, while Microsoft documents the fix in KB5124010.
Windows 11 File History bug: what broke
File History automatically saves copies of files from locations such as Documents, Pictures, Videos and Music to an external drive or network location. It is separate from Windows Backup and is designed to let users restore earlier versions of individual files.
The September update did not necessarily produce an obvious failure. A drive could remain connected and usable while File History stopped completing its job. That makes the Windows 11 File History bug a data-protection problem rather than a simple storage warning. It also follows other recent Windows update problems, including the September USB audio issue.
How to fix the Windows 11 File History bug
Microsoft’s optional KB5124010 preview update, released on September 22, includes a fix for File History on Windows 11 24H2 and 25H2. Open Settings, go to Windows Update, then Advanced options and Optional updates. If KB5124010 is offered, install it and restart the PC.
After updating, open File History and confirm that the external or network drive is recognised. Check that a recent backup timestamp is appearing rather than assuming the warning has cleared. If the update is not offered, Microsoft says the fix will arrive through the normal Windows update cycle. Windows 11’s recent update problems are a reminder to check the result, not just the installation status.
Should I install KB5124010 immediately?
If File History is part of your backup plan, installing the optional update is sensible after checking that it is offered for your Windows 11 version. Restart afterwards and verify a new backup completes.
Does File History back up the whole PC?
No. File History is mainly for earlier versions of personal files and folders. It is not a complete system-image replacement, so keep another backup for the wider machine if the data matters.
What if KB5124010 is not available?
Microsoft says the File History fix will roll into the normal Windows update cycle. Until then, check recent backup timestamps and use another working copy of important files.
