Windows File History bug fix released after September update issues
Microsoft addresses backup failures caused by recent security patch
1Widespread backup failures
Microsoft's September 2026 security update caused File History to malfunction across all current Windows 11 versions (26H1, 25H2, 24H2, 23H2) and Windows 10 ESU systems. Users experienced failed backups, incorrect drive connection messages, and missing file version errors despite proper setup. The issue stems from conflicts with FileHistory.exe and KERNELBASE.dll components, visible through Event Viewer logs showing application crash errors.
2Diagnosing the problem
Affected users can verify the bug by checking Windows Event Viewer for specific error events. The diagnostic path involves navigating to Application logs, filtering for Error-level events from Application Error source, and searching for FileHistory.exe or KERNELBASE.dll references. This confirmation step helps determine if backup failures stem from the September update rather than hardware or configuration issues.
3File History's legacy status
While still technically supported, Microsoft considers File History a legacy feature no longer in active development. The company recommends OneDrive or Windows Backup as modern alternatives for file synchronization and recovery. However, File History remains popular for its straightforward folder-specific backup capability, particularly for user account directories like Documents, Pictures, and Desktop.
4Preview update solution
Microsoft released an optional Windows 11 preview update (KB5124006 for 26H1, KB5124010 for 25H2/24H2) on September 26, 2026 to fix the File History bug. Users must manually install this update through Windows Update settings. Despite being a preview release that typically carries some risk, it's currently the only available fix for affected Windows 11 systems until the October Patch Tuesday rollout.
5Older version challenges
Windows 11 23H2 and Windows 10 ESU users face different circumstances. Microsoft no longer supports 23H2, while Windows 10 only receives security updates through Extended Security Updates. The company acknowledges the File History issue on these systems but hasn't provided a timeline for fixes, leaving users dependent on the legacy feature without immediate solutions.
6Update installation process
To apply the fix, users navigate to Settings > Windows Update and look for the 2026-09 Preview Update with appropriate KB number. The installation requires manual initiation through the Download button. Microsoft cautions that preview updates may contain other bugs, creating a trade-off between restoring File History functionality and potential system instability until the official October patch.
7Enterprise backup considerations
The File History disruption highlights risks of relying on deprecated features in professional environments. Organizations using File History for business continuity must weigh the convenience of built-in solutions against Microsoft's shifting priorities toward cloud-based alternatives. The incident underscores the importance of maintaining multiple backup methods beyond OS-native tools.
8Future of file backup
This incident accelerates Microsoft's push toward modern backup solutions, with File History likely facing eventual discontinuation. Users dependent on local backup methods should evaluate migration to Windows Backup or third-party alternatives. The temporary fix maintains functionality but reinforces Microsoft's long-term strategy favoring cloud integration over standalone backup tools.
Original article: Latest news — Windows File History bug fix released after September update issues