If you use Windows File History to protect your documents, photos, and other important files, now is a good time to make sure your backup is actually running.
Microsoft has confirmed a problem associated with the September 2026 Windows security update that can prevent File History from creating or updating backups on some computers. An affected PC may even tell you to ?Reconnect your drive? when the backup drive is already connected and working normally. Microsoft Support
The issue is a useful reminder of something that applies to every backup system: having a backup drive connected does not necessarily mean your files are being backed up.
What Microsoft Has Confirmed
File History is a Windows feature that automatically saves copies of personal files to an external drive or network location. Those copies can then be used to recover deleted files or restore an earlier version of a file that was changed or damaged. Microsoft Support
According to Microsoft's September 2026 update documentation, some File History users may experience problems creating or updating backups after installing the September security update.
Microsoft lists several possible symptoms:
- A ?Reconnect your drive? message even though the backup drive is connected.
- The Last Backup date and time may stop updating.
- Previously backed-up files may report ?No previous version available.?
- In some cases, Windows Event Viewer may show File History application crashes involving
FileHistory.exe.
Microsoft added the File History problem to its known-issues information on September 19, 2026 and says it is working on a resolution for a future Windows update. Microsoft Support
How to Tell If File History May Be Affected
You do not need to assume something is wrong simply because you installed the September update.
Instead, check whether File History is actually completing backups.
Open Control Panel, select System and Security, and then open File History.
Look for your normal backup drive or network location. If Windows suddenly says that the drive needs to be reconnected?even though it is connected?that may be one of the symptoms Microsoft has documented.
You should also pay attention to the date of your most recent backup. If that date has stopped advancing, don't assume File History is still protecting new or changed files.
Microsoft normally recommends checking the physical connection when a genuine ?Reconnect your drive? message appears. With the newly acknowledged September issue, however, the message itself may sometimes be incorrect. Microsoft Support
What You Should Check Right Now
A few simple checks can tell you a great deal:
Make sure your backup drive is connected. If it is an external USB drive, verify that Windows can see and access it normally.
Open File History and check its status. Go to Control Panel ? System and Security ? File History.
Look at the most recent backup information. Make sure it reflects a recent backup rather than a date from several days ago.
Try a manual backup. File History provides a Run now option. After it completes?or attempts to complete?check the status again.
Verify that you can recover something. For an important folder that is supposed to be protected by File History, you can right-click it in File Explorer and look at Restore previous versions. Microsoft documents this as one method of accessing File History backups. Microsoft Support
Most importantly, do not erase, reformat, or replace a backup drive simply because Windows suddenly reports that it needs to be reconnected. If the drive itself is accessible, the message could be related to the current Windows issue rather than a failed drive.
Don?t Rush to Remove the Security Update
It can be tempting to uninstall an update when a problem appears immediately afterward.
In this situation, I would be cautious about doing that.
The September update is a security update, and removing security updates can restore vulnerabilities that the update was intended to correct. Microsoft has acknowledged the File History problem and says a resolution is being developed. Microsoft Support
Unless there is an urgent reason to roll back an update, waiting for Microsoft's correction while making sure your important data is protected another way may be the better approach.
If you are unsure, have someone evaluate the computer before removing updates or making major changes to your backup configuration.
The Bigger Lesson: Verify Your Backups
This particular Windows problem will eventually be fixed, but there is a broader lesson worth remembering.
A backup is only useful if it is actually working when you need it.
Automatic backups are convenient precisely because they normally operate quietly in the background. The downside is that weeks or months can sometimes pass before anyone notices that a backup stopped running.
Every so often, check:
- When the last successful backup occurred.
- Whether the backup destination is still available.
- Whether newly created or changed files are being protected.
- Whether you can actually retrieve a backed-up file.
For a broader look at backup planning and what happens when systems go down, see our recent article: If Your Computers Went Down Today, Could Your Business Keep Working?
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When It Makes Sense to Get Help
If File History suddenly stopped working, your backup drive is behaving strangely, or you're simply not sure whether your important files are protected, it is worth checking the system before something is lost.
PC Pros can help troubleshoot Windows and backup problems, check the condition of your storage devices, and help make sure your backup strategy is doing what you expect it to do.
For PC Pros customers in Virginia Beach and surrounding areas, the goal isn't simply to make an error message disappear. It's to make sure the files behind that error message are actually protected.
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Sources
Microsoft ? September 8, 2026?KB5124008 (OS Builds 26200.9445 and 26100.9445)
Documents the September 2026 File History issue, including the false ?Reconnect your drive? message, backup timestamp problems, and Microsoft?s current status. Microsoft Support
Microsoft KB5124008 update information
Microsoft ? Backup and Restore with File History
Explains how File History works, how to configure it, and how to restore previous versions of files. Microsoft Support
Microsoft ? Reconnect Your File History Drive in Windows
Provides Microsoft?s normal troubleshooting guidance for File History drive connection warnings. Microsoft Support
Microsoft File History reconnect guidanceed.