Microsoft has released optional preview updates for Windows 11 to address a widespread issue that caused the legacy File History feature to stop creating or updating file backups. The fix arrives shortly after system administrators and home users reported persistent backup failures following the rollout of the mandatory September Patch Tuesday security update.

Users running impacted builds can now install optional cumulative updates KB5124010 and KB5124006 to restore automated file protection. Without this patch, affected systems remain unable to update file versions on connected external drives or network-attached storage targets.

microsoft fixes windows 11 file history bug

The optional non-security update delivers a direct patch for the File History process, resolving underlying crash events and incorrect drive disconnect warnings that appeared during scheduled backup routines.

The issue originated after Microsoft confirmed that September security updates caused File History backup failures across modern versions of the operating system. While Microsoft released the Windows 11 KB5124010 update preview to resolve the problem for main builds, users must opt in manually through Windows Update to apply the fix before the next mandatory patch release.

Microsoft Addresses Widespread Windows 11 File History Backup Failures

File History, originally introduced in Windows 8, remains a popular utility for users who prefer local file versioning over cloud storage. The tool automatically scans designated user directories, including Documents, Pictures, Music, Videos, and Desktop, and saves copies to a designated external hard drive or network path.

Following the September update, users found that File History failed to execute scheduled tasks silently in the background. Instead of preserving incremental changes, affected systems stopped updating saved versions without notifying the user. In many instances, opening the File History control panel presented users with an error stating that their backup drive needed to be reconnected, even when the external disk was plugged in and fully accessible.

Symptoms and Event Viewer Crashes Triggered by September Update

System diagnostic logs revealed that the failure was caused by application crashes within the operating system's core binaries. When File History attempted to start a scheduled sync cycle, the process crashed unexpectedly, generating error entries inside the Windows Event Viewer.

Technical reports logged in Event Viewer highlighted recurring application faults pointing directly to FileHistory.exe and KERNELBASE.dll. These background crashes prevented the system from updating the "Last Backup" timestamp in the Control Panel. Furthermore, inspecting file properties on backed-up items showed a message reading "No previous version available," leaving users without access to historical file snapshots.

This disruption caused significant friction for users relying on local backups, especially coming alongside other post-patch issues where September Windows 11 updates broke enterprise Always On VPN connections.

Optional Cumulative Update Delivers Official Backup Fix

Microsoft acknowledged the bug on its official health dashboard and included a fix within the latest optional cumulative updates. The fix is delivered in update KB5124010 for devices running Windows 11 24H2 and 25H2, while devices running preview build 26H1 receive update KB5124006.

In its official release notes, Microsoft confirmed the resolution, stating:

"This update addresses an issue where File History might fail to back up or restore files to an external drive or network location. Affected devices might incorrectly display a 'Reconnect your drive' message even when a compatible backup drive is connected and working properly."

While the update resolves automated background processing, early feedback indicates that manual trigger operations inside the classic Control Panel interface may still show minor timestamp synchronization delays for certain configurations. However, background automated backups resume normal operation once the update is applied.

Installation Steps and What to Expect Before Patch Tuesday

Because preview releases are optional, Windows 11 will not install KB5124010 or KB5124006 automatically. Users affected by the File History issue must initiate the download through the system settings menu.

  • Open the Settings app from the Start menu or press Win + I.
  • Navigate to the Windows Update tab.
  • Select Advanced options and click on Optional updates.
  • Locate the 2026-09 Preview Update corresponding to your Windows version and click Download & install.
  • Restart your computer when prompted to finalize the installation.

Users who prefer not to install preview builds can wait for the fixes to be incorporated into the mandatory Patch Tuesday release scheduled for October. However, installing the optional update now is the only official way to restore File History functionality immediately without uninstalling security patches.

Closing Remarks

The release of KB5124010 and KB5124006 provides a quick resolution for Windows 11 users who depend on File History for local data protection. Although Microsoft continues to emphasize cloud-based solutions like OneDrive and the modern Windows Backup app, this prompt patch demonstrates ongoing support for critical local backup features. Affected users are encouraged to install the optional update or verify their alternative backup systems until the October general release arrives.