Microsoft Confirms September 2026 Windows Updates Break File History Backups
Brief
Microsoft has confirmed that its September 2026 Windows security updates can prevent File History from creating or updating backups on some systems.
The regression places users who rely on the built-in feature at risk of assuming their files are protected when no recent backup has actually completed.
File History is a Windows backup capability accessed through Control Panel under System and Security. It periodically copies files to an external drive or network location and retains earlier versions, allowing users to recover documents that were accidentally changed, corrupted, or deleted.
September updates Break File History Backup
Microsoft added the problem to its known-issues documentation on September 19, following the September 8 security update rollout.