Windows 11 File History Stopped Working After the September Update: How to Fix It

A Windows update has caused a problem that could leave some users without recent File History backups, even though the backup feature appears to be configured normally.

Microsoft has confirmed that its September 2026 security updates can cause File History to stop creating or updating backups. On affected PCs, Windows may incorrectly report that the backup drive needs to be reconnected, even when the drive is connected and working properly. The Last Backup timestamp may also stop updating and previously backed-up files may show “No previous version available.”

If you use File History, don’t assume your files are being backed up just because the feature is enabled. Here’s how to check whether your backups were affected, and recover files if a required backup copy was never created.

What Happened to File History After the September 2026 Windows Update?

Microsoft’s September 2026 Windows security updates can cause File History to stop creating or updating backups on affected systems. File History is a Windows feature that automatically saves copies of files to an external drive or network location. It can then be used to restore earlier versions of files that were accidentally deleted, modified, or damaged.

The problem surfaced after the September security updates. Microsoft says affected systems may be unable to create or update File History backups. Windows can also incorrectly display a “Reconnect your drive” message even though the configured backup drive is connected and functioning correctly.

The issue can be particularly difficult to notice because there may be no obvious indication that new backups have stopped.

For example, you could continue working on documents, photos, or other files while assuming File History is protecting them in the background. If the backup process has actually stopped, however, the latest versions of those files may not exist in the File History archive.

Microsoft also lists other symptoms, including:

• The Last Backup timestamp stops updating.
• Previously backed-up files show “No previous version available.”
• File History may fail to back up or restore files.
• Event Viewer may contain application crash events referencing FileHistory.exe and KERNELBASE.dll.

Which Microsoft Updates Are Affected?

The September issue is associated with the following Windows updates:

Microsoft’s release information lists File History as a known issue across affected Windows releases.

Note: The originating update is not necessarily the update you should uninstall. Microsoft has since released fixes for the problem, so installing the appropriate fix is the better first step. For Windows 11 24H2 and 25H2, that fix is KB5124010, released September 22, 2026.

How to Check If Windows 11 File History Stopped Working

Before changing anything, check whether File History has actually been creating backups. This is important because the problem can be easy to miss until you need to restore a file.

1.      Check the Last Backup Timestamp

Go to Control Panel > System and Security > File History and look for the last Backup information. If the timestamp is significantly older than expected or hasn’t changed since you installed the September update, your recent files may not have been backed up. A stale timestamp by itself doesn’t prove that the September bug is responsible, but it is a good reason to investigate further.

2.      Look for the “Reconnect your drive” message

In File History, check whether Windows asks you to reconnect your drive. If the external backup drive is connected and you can open it normally in File Explorer, the warning could be related to the September File History bug rather than a disconnected or failed drive. Microsoft specifically lists this incorrect warning as one of the symptoms of the issue.

3.      Check Whether Previous Versions Are Available

You can also test a file that you know was previously protected by File History. Right-click the file and look for its available previous versions. If Windows suddenly reports: No previous version available, even though older versions were previously being maintained, File History may have been affected. Microsoft lists this as another symptom of the September issue.

4.      Check Event Viewer

If you want additional confirmation, check Windows Event Viewer.

• Press Win + X
• Select Event Viewer
• Go to Windows Logs > Application

• Look for recent applications crash events.
• Check whether they reference FileHistory.exe or KERNELBASE.dll.

Microsoft says these events may appear on affected systems.

How to Recover Files That Were Not Backed Up?

If File History stopped working before it could create a backup of your latest files, the required copy may not exist on the backup drive. In this case, you may still be able to recover the lost files from the original Windows drive, provided their data has not been overwritten.

Stellar Data Recovery Professionalcan help scan the affected drive for deleted or lost files and preview the recoverable data before you save it. It supports recovery from both internal and external storage devices, making it useful when a file was lost while File History was not creating new backups.

• Download, install and launch Stellar Data Recovery Professional on your PC.
• On the What to Recover screen, select the type of data you want to recover.
• On the Recover From screen, select the drive volume in which you want to search for lost files.
• Click Next.

• On the Recover From screen, select the drive volume in which you want to search for lost files.

• Click Scan.A screen displaying the scanning process will appear.

• Recovered files will be displayed for you to Preview.

• Select the files you want to retrieve and click Recover to save them to a different drive.

Summing Up

The September 2026 Windows update caused File History to stop creating or updating backups on affected systems, potentially leaving users without recent copies of their files. If you use File History, check the Last Backup timestamp and verify that new backups are being created after installing Microsoft’s fix.

If a file was lost while File History wasn’t working and no backup copy exists, avoid using the affected drive unnecessarily. You may still be able to recover the missing file with a data recovery tool, such as Stellar Data Recovery Professional, provided its data hasn’t been overwritten. Most importantly, don’t rely on a backup feature simply because it is enabled and periodically verify that your backups are actually running and that you can restore your files.