Windows bugs and fixes September 24 2026: File History
Chapters
TL;DR
File History backups broke on Windows after the September 2026 security updates, BleepingComputer reported on September 24, 2026. Microsoft has shipped the fix in optional updates KB5124006 for Windows 11 26H1 and KB5124010 for Windows 11 24H2 and 25H2; otherwise, the fix is scheduled for October 13.
- BleepingComputer reported on September 24, 2026 that affected PCs could show "Reconnect your drive" even with a working backup drive attached.
- BleepingComputer reported on September 24, 2026 that KB5124006 and KB5124010 fix File History backup and restore failures.
- Notebookcheck reported on September 23, 2026 that KB5124010 fixes a 0x139 Bluetooth audio crash and an incorrect Bluetooth toggle.
- BleepingComputer reported on September 24, 2026 that people who skip the optional updates are scheduled to receive the File History fix on October 13.
What broke on Windows?
BleepingComputer said on September 24, 2026 that File History could not create or update backups on some Windows systems.
The affected systems include Windows 10 21H2 or later, Windows 10 Enterprise LTSC 2016/2019, and Windows 11 23H2 and later, according to BleepingComputer on September 24, 2026. Symptoms include "Reconnect your drive" alerts with a compatible drive connected, a stalled "Last Backup" timestamp, and "No previous version available" for files already backed up.
BleepingComputer explained on September 24, 2026 that File History copies Documents, Music, Pictures, Videos, and Desktop data to an external drive or network storage location. The Windows 11 bug therefore affects both new backups and access to older versions rather than merely displaying a harmless warning.
For the earlier chronology, read September security updates stop File History seeing backup drives on Windows 11. I treat a stopped backup as a current data-protection failure, even when existing files remain visible on the PC.
Which File History fixes have shipped?
The Windows update fix has shipped as KB5124006 for Windows 11 26H1 and KB5124010 for Windows 11 24H2 and 25H2.
BleepingComputer reported on September 24, 2026 that KB5124006 and KB5124010 carry the File History fix.
BleepingComputer's KB5124010 report, published September 24, 2026, describes KB5124010 as an optional non-security preview update with 46 changes and fixes. Optional monthly updates contain quality improvements rather than security fixes, according to the same report.
People who do not install the optional updates are scheduled to receive the File History correction with the October 13 Patch Tuesday updates, BleepingComputer reported on September 24, 2026. Waiting avoids an optional preview package, but the cost is leaving File History backup or restore unavailable until the scheduled rollout.
| Windows version | Update | File History status | Source and date |
|---|---|---|---|
| Windows 11 26H1 | KB5124006 | Fix shipped in an optional cumulative update | BleepingComputer, September 24, 2026 |
| Windows 11 24H2 and 25H2 | KB5124010 | Fix shipped in an optional cumulative update | BleepingComputer, September 24, 2026 |
| Eligible systems waiting for the regular rollout | October 13 Patch Tuesday updates | Fix scheduled but not yet installed | BleepingComputer, September 24, 2026 |
What else does KB5124010 fix?
KB5124010 also fixes Bluetooth crashes, an incorrect radio toggle, File Explorer faults, and several desktop reliability problems on Windows 11. Notebookcheck reported on September 23, 2026 that KB5124010 fixes a 0x139 crash during Bluetooth audio streaming.
Notebookcheck also reported on September 23, 2026 that the update corrects a Bluetooth control that could appear on while the radio was off, improves cloud-file thumbnails, and stops clicks near the File Explorer address bar from erasing typed text.
BleepingComputer's September 24, 2026 report says KB5124010 improves microphone compatibility with certain Bluetooth Classic audio accessories and the reliability and performance of LE Audio accessories. It also adds settings that can remap the Copilot key to Right Ctrl or Context Menu.
Notebookcheck said on September 23, 2026 that Microsoft had disclosed two new known issues with the preview update, but the available account does not identify their symptoms. I cannot say who is affected or offer a specific workaround without those details.
What has Microsoft acknowledged?
Microsoft has acknowledged the File History failure and says the optional updates address it. Microsoft acknowledged the File History failure, BleepingComputer reported on September 24, 2026.
The same BleepingComputer report, published September 24, 2026, quotes Microsoft saying, "This update addresses an issue where File History might fail to back up or restore files to an external drive or network location." That wording covers both the creation of backups and restoration from compatible local or network storage.
For this File History fault, Microsoft acknowledged the issue and identified KB5124006 and KB5124010 as the corrective updates. My position is that Microsoft publishes its own known issues, their workarounds and their fix builds on release health and in the KB articles, so a Windows problem that looks mysterious on a help desk queue is usually already documented, dated and attributable.
Journalists still provide useful chronology and independent summaries. Microsoft's acknowledgment is the decisive evidence for the File History status, while BleepingComputer's September 24, 2026 account connects the failure to the exact corrective updates.
What can a person do today?
Install the matching optional update if File History is failing and a working backup or restore is needed now. PCWorld said on September 23, 2026 that KB5124010 can be installed manually through Windows Update settings.
BleepingComputer reported on September 24, 2026 that installation requires selecting "Download and install" unless "Get the latest updates as soon as they're available" is enabled. On Windows 11 26H1, the named File History update is KB5124006; on Windows 11 24H2 or 25H2, it is KB5124010.
People who can tolerate the broken backup can wait for the scheduled October 13 rollout, according to BleepingComputer on September 24, 2026. The trade-off is plain: waiting avoids an optional preview update but leaves File History unable to create, update, or restore backups on an affected PC.
On a managed work computer, check the named update in Windows Update and follow the applicable update policy. Ordinary users can still read the named update in Windows Update and make an informed choice. I would verify that File History completes a backup after installation rather than treating disappearance of the alert as proof.
Frequently asked questions
Does KB5124010 contain security fixes?
No. BleepingComputer reported on September 24, 2026 that KB5124010 is an optional non-security preview update containing quality improvements.
Can I wait instead of installing the optional File History fix?
Yes. BleepingComputer reported on September 24, 2026 that the fix is scheduled to arrive with the October 13 Patch Tuesday updates for people who skip the optional packages.
Does KB5124010 fix the Bluetooth audio blue screen?
Yes. Notebookcheck reported on September 23, 2026 that KB5124010 fixes the 0x139 blue screen triggered during Bluetooth audio streaming.