Microsoft September 2026 Updates Disrupt Windows File History Backup Feature
What Happened — Microsoft’s September 2026 cumulative security updates cause the built‑in File History backup utility to stop creating or updating backups on affected Windows 10 and Windows 11 systems. Users see crash events (FileHistory.exe, KERNELBASE.dll), “Reconnect your drive” prompts, stale timestamps, and missing version history.
Why It Matters for Trust & Control Assurance
- Backup continuity is a core control objective; a broken backup defeats evidence‑preservation and recovery requirements that continuous‑control programs must demonstrate.
- The incident highlights the need for independent control mapping and evidence collection to prove that backup processes remain effective despite upstream patch changes.
Who Is Affected – Enterprises and consumers running Windows 10 21H2 or later, Windows 10 Enterprise LTSC 2016/2019, and Windows 11 23H2 or later.
Recommended Actions – Validate that File History is still operational after each patch; if not, switch to an alternative backup solution, document the deviation, and capture remediation evidence for audit trails. Source: BleepingComputer
Technical Notes – The failure is linked to specific KB articles (e.g., KB5124012, KB5122878). Symptoms include Event Viewer errors referencing FileHistory.exe/KERNELBASE.dll, incorrect “Reconnect your drive” messages, and unchanged “Last Backup” timestamps. Microsoft has issued out‑of‑band fixes for related issues but not yet for this backup problem. Source: same