Microsoft: September 2026 Windows Updates Disrupt File History Backups

En bref

• Microsoft has warned that updates released in September 2026 can interfere with File History.
• The problem affects a subset of Windows systems, not every installation.
• Backup operations may fail, leaving recovery points incomplete or missing.
• No CVE is tied to the issue, and severity is rated medium.
• Admins should verify File History status and consider alternate backup methods.

Microsoft has notified customers that Windows updates released in September 2026 can disrupt File History, the built-in backup utility. On impacted devices, the feature may stop working as expected and scheduled backup jobs can fail. The company has issued a warning about the regression, but no CVE has been assigned because this is a reliability problem rather than an exploitable vulnerability.

The scope appears limited to some systems rather than all Windows installations. Organizations that depend on File History for endpoint or user-file protection, including K-12 districts, may find that backups are not completing even when the interface suggests otherwise. Districts using File History as a lightweight backup layer should treat affected machines as potentially unprotected until they confirm otherwise.

This matters because silent backup failures can create a false sense of security. If a device is lost, damaged, or hit by ransomware, missing recovery points can turn a manageable incident into permanent data loss. For schools, that can include staff documents, instructional materials, and other district records that may not exist elsewhere.

Microsoft's monthly updates occasionally introduce regressions in older components, and File History is a legacy feature that may not receive the same testing focus as newer backup and sync tools. The medium severity rating reflects the limited scope and the absence of an exploit, but the operational risk is still real for affected endpoints.

What to watch: Microsoft's known-issues documentation, any revised guidance or workaround, and a future cumulative update that resolves the breakage. In the meantime, IT teams should check backup logs, test restores, and ensure critical data is protected through an alternative method until the vendor fix is available.

À faire maintenant

1. Audit Windows endpoints updated in September 2026 and check whether File History is enabled and completing backups.
2. Pause or stage the September 2026 update rollout for remaining systems until Microsoft confirms a fix or workaround.
3. Test restores of sample files from File History rather than relying only on the backup status shown in the interface.
4. Move critical district data to an alternative backup or cloud sync solution temporarily while the issue remains unresolved.
5. Review File History event logs and error details, document failures, and open a support case with Microsoft if needed.
6. Pilot Microsoft's latest cumulative update or documented workaround in a small ring before broad deployment.
7. Notify staff about possible backup gaps and remind them to store important files in approved, protected locations.

Source originale

BleepingComputer