Microsoft: September updates break File History backup feature

Microsoft warned that the built-in File History backup feature in Windows may stop working on some systems after installing the September 2026 security updates.

File History (introduced in Windows 8 and replaced by Windows Backup, which backs up data to OneDrive) automatically saves copies that let users recover accidentally deleted or damaged files using an older version from hours, days, or weeks ago.

By default, File History backs up all folders under the user's account profile (Documents, Music, Pictures, Videos, and Desktop) to an external hard drive, such as a USB flash drive, or a network storage location (NAS).

In a service alert seen by BleepingComputer and first spotted by Microsoft MVP Susan Bradley, Microsoft says that affected customers can see application crash events in Event Viewer referencing FileHistory.exe and KERNELBASE.dll.