[File History (known issue)] Fixed: 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.
Both updates are optional Windows 11 updates that you must install manually; otherwise, the fix will roll out as part of October’s Patch Tuesday. In other words, if you don’t install this optional update, the File History bug will persist until next month. To install the update, check Windows Settings → Windows Update → Advanced options → Optional updates.
Original story from September 22nd, 2026: Many users who have installed the latest September security patches for Windows have found that the “File History” feature no longer works—deleted or corrupted files can no longer be recovered.
File History automatically saves copies of files, allowing users to recover accidentally deleted or corrupted files using older versions that were stored hours, days, or weeks ago. By default, File History backs up all folders in the user profile (Documents, Music, Pictures, Videos, and Desktop) to an external drive, such as a USB flash drive or a network attached storage (NAS) device.
According to Microsoft, the issue is due to a bug that occurs in all current versions of Windows 10 and 11, including 21H2, 22H2, 23H2, 24H2, 25H2, and 26H1. Microsoft wrote on this support page and this one:
After installing the September 2026 Windows security update, some customers using File History, might be unable to create or update backups. File History, available through Control Panel > System and Security > File History, is used to back up 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 functioning properly. Additionally, the “Last Backup” timestamp might not update, and previously backed up files might show “No previous version available.” In some cases, Event Viewer might record application crash events referencing FileHistory.exe and KERNELBASE.dll.
There’s currently no fix for the issue, though Microsoft says it is “working on a resolution” that’ll come in a future Windows update. Until an official fix is released, the best solution is to uninstall the security update, which you can do by rolling back a problematic Windows update.