Microsoft rolls out optional fix for Windows File History backup glitch
A September Patch Tuesday update has caused File History backups to fail on supported Windows 11 and Windows 10 ESU systems, with users seeing drive reconnection prompts and missing backup timestamps. Microsoft has released an optional preview update to address the issue, but it does not cover Windows 11 23H2 or Windows 10. Affected users can verify the problem via Event Viewer entries referencing FileHistory.exe or KERNELBASE.dll.
The September Patch Tuesday security update introduced a compatibility problem with File History, a legacy backup utility still used by many Windows customers. Microsoft's support documentation confirms the bug affects all supported Windows 11 editions and Windows 10 systems enrolled in Extended Security Updates. Users may see false drive reconnection prompts or lose access to previously saved file versions.
Microsoft has responded with an optional preview update carrying different KB numbers depending on the Windows edition. Windows 11 26H1 users receive KB5124006, while 25H2 and 24H2 users receive KB5124010. The company positions File History as a legacy tool, directing users toward OneDrive and Windows Backup instead. Windows 11 23H2 and Windows 10 users remain without a fix until October's Patch Tuesday.
Users who depend on File History for routine backups could face data loss risks if the glitch goes unnoticed, particularly those who assume backups are running when they are not. Small businesses and home users without alternative backup systems may be most affected. The delayed fix for older Windows versions could pressure some users to upgrade or adopt Microsoft's newer backup services, potentially shifting how people manage local data recovery.