Windows File History Broken After September 2026 Updates? Here’s What IT Admins Need to Know
The September 2026 Patch Tuesday updates introduced an unexpected issue impacting Windows File History, leaving many organizations with failed backups, broken restores, and confusing error messages. If your users rely on File History as part of their endpoint recovery strategy, this is a problem worth addressing immediately.
The Issue: File History Failures Across Windows 10 and Windows 11
Following the September 2026 security updates, administrators began reporting problems with Windows File History on both Windows 10 and Windows 11 devices.
Affected systems may experience:
- File History backups failing unexpectedly
- Restore operations not completing successfully
- Persistent “Reconnect your drive” prompts even when the backup target is available
- Application crashes involving FileHistory.exe and KERNELBASE.dll
- Users losing confidence in local recovery options due to backup failures
For organizations that still leverage File History for workstation-level protection, this bug can significantly impact recovery readiness and support operations.
Microsoft’s Response
Microsoft has acknowledged the issue and released optional out-of-band updates to resolve the problem:
- KB5124010
- KB5124006
These updates specifically address the File History backup and restore failures introduced by the September security updates.
What Endpoint Teams Need to Know
1. These Updates Are Optional
One of the most important details is that these fixes are not deployed automatically through standard Patch Tuesday servicing.
Unless administrators:
- Approve the updates,
- Deploy them through management tools,
- Or instruct users to install them manually,
affected devices will remain vulnerable to the File History issue until the next cumulative update is released.
2. Waiting for October Is an Option
If your organization avoids optional updates due to change management policies, you may choose to wait for the October cumulative release, which is expected to include the fix.
However, this means users may continue experiencing backup and restore failures in the meantime.
3. Rollback Remains a Temporary Workaround
Organizations heavily dependent on File History may consider:
- Rolling back the September security update on impacted devices
- Deploying Microsoft’s optional fix
- Waiting for the October cumulative update
The best approach will depend on your organization’s patching strategy, risk tolerance, and backup requirements.
Recommendations for IT Administrators
Before taking action, consider the following:
✅ Verify whether File History is actively used within your environment
✅ Identify affected Windows 10 and Windows 11 endpoints
✅ Test KB5124010 and KB5124006 in a pilot group
✅ Communicate with support desks about potential File History failures
✅ Document any recovery limitations while remediation is underway
✅ Include the fix in your endpoint management and patching plans where appropriate
Final Thoughts
This incident serves as another reminder that even routine security updates can introduce unexpected side effects. Organizations relying on built-in Windows backup technologies should validate backup functionality after major patches and maintain alternative recovery methods whenever possible.
For environments where File History remains a critical component of endpoint protection, deploying the optional updates may be the quickest path to restoring backup and recovery reliability.
Discussion
Are you deploying the optional fixes immediately, or are you waiting for the October cumulative update to roll out? Let us know how your organization is handling the File History issue.