Windows bugs and fixes for September 27, 2026
Chapters
What broke on Windows 11?
Cybersecuritynews said on September 25, 2026, that Windows 11 could show a black screen after sign-in.
Cybersecuritynews also said on September 25, 2026, that affected users may authenticate successfully but never reach a usable desktop because the Windows shell does not start automatically. Application event logs may show Windows Explorer crashes, and manually starting the desktop session may restore access.
BleepingComputer attributed the problem on September 25, 2026, to KB5120996 on Windows 11 version 26H1 and KB5120998 on Windows 11 versions 25H2 and 24H2. The report said the issue mainly affects Azure Virtual Desktop hosts using FSLogix.
Cyberpress reported on September 26, 2026, that the affected shell controls the taskbar, Start menu, desktop icons, and File Explorer, explaining why a running session can appear unusable. Cyberpress also said Microsoft classified the incident as mitigated on September 24, while a permanent code fix was still expected in a future Windows update.
Cyberpress's September 26, 2026 account continues the chronology in my Windows bugs and fixes September 26 2026: black screen coverage.
TL;DR
Cybersecuritynews reported on September 25, 2026, that Windows 11 updates could leave AVD hosts using FSLogix at a black screen after sign-in. Microsoft has mitigated the desktop problem, but no permanent fix has shipped. Tech Insider reported on September 24, 2026, that KB5124010 fixes File History, while Neowin reported on September 25, 2026, that game crashes associated with KB5124010 remain unacknowledged.
- Cybersecuritynews, September 25, 2026: Microsoft lists the black-screen incident as mitigated, not permanently fixed.
- BleepingComputer, September 25, 2026: manually starting
explorer.execan restore the desktop temporarily. - Tech Insider, September 24, 2026: KB5124010 resolves the File History failure caused by KB5124008.
- Neowin, September 25, 2026: reported KB5124010 game crashes have no Microsoft acknowledgment.
Has a permanent black-screen fix shipped?
BleepingComputer said on September 25, 2026, that no permanent fix was available.
BleepingComputer reported on September 25, 2026, that Microsoft had instead supplied Known Issue Rollback policies for enterprise-managed computers affected after KB5120996, KB5120998, KB5124008, or KB5122880. Windows 11 version 26H1 requires KB5124006 Known Issue Rollback, while versions 25H2 and 24H2 require KB5124010 Known Issue Rollback.
BleepingComputer said on September 25, 2026, that an administrator must install and configure the matching Group Policy and restart every affected device. The rollback disables the problematic change until Microsoft releases a resolution in a future Windows update.
I read the Windows known issues status narrowly. Mitigated means Microsoft has provided a way around the regression, according to BleepingComputer on September 25, 2026, but it does not mean corrected code has reached ordinary Windows Update installations.
On a managed AVD host, the KIR requires an administrator to configure the policy and restart the device, as BleepingComputer documented on September 25, 2026. A person at the keyboard can still restore a blocked session manually while that managed change is prepared.
Which Windows fixes have shipped?
Tech Insider said on September 24, 2026, that KB5124010 fixed File History.
Tech Insider reported on September 24, 2026, that KB5124008 could prevent File History from creating or updating backups through Control Panel > System and Security > File History. Microsoft documentation said the failure was resolved in updates released on and after September 22, 2026, including KB5124010.
That Windows update fix matters because the failure could remain quiet rather than presenting as an obvious crash, according to Tech Insider on September 24, 2026. I would verify that File History has resumed creating versions after installing the corrective update rather than assuming installation alone proves that backups restarted.
Notebookcheck reported on September 23, 2026, that KB5124010 also fixes a 0x139 blue-screen crash during Bluetooth audio streaming. The same update corrects a Bluetooth toggle that could appear enabled while the radio was off, File Explorer thumbnail and address-bar failures, and several desktop-background problems.
Neowin reported on September 22, 2026, that KB5124010 is a preview update for Windows 11 versions 25H2 and 24H2. Neowin said its features include File Explorer preview changes, cloud-file thumbnail improvements, touchpad scrolling controls, and desktop-background reliability work.
What remains unconfirmed?
Neowin said on September 25, 2026, that Microsoft had not acknowledged the reported game crashes.
Neowin reported on September 25, 2026, that Battlefield 6 could crash to the desktop roughly 15 to 30 seconds after launch following KB5124010, often without an error message. Reports also named Wardogs and other games using Easy Anti-Cheat, irrespective of the hardware used.
Neowin said on September 25, 2026, that an anti-cheat conflict was suspected, but Microsoft had neither acknowledged the Windows 11 bug nor supplied an official cause. I therefore cannot call KB5124010 the confirmed cause, even though the timing and repeated user reports justify caution.
No Microsoft repair is named in Neowin's September 25, 2026 report. The honest status is an unacknowledged report with no sanctioned workaround, not a documented Windows KB update problem with a published resolution.
The distinction matters at the keyboard. Microsoft documentation gives a precise shell workaround and KIR for the black screen, according to BleepingComputer on September 25, 2026, while the game reports provide neither a confirmed trigger nor an official remediation.
What can you do today?
BleepingComputer said on September 25, 2026, that manually launching explorer.exe can restore the desktop temporarily.
For a black screen after sign-in, BleepingComputer instructed affected users on September 25, 2026, to press Ctrl+Shift+Esc, select Run new task, enter explorer.exe, and select OK. The cost is that the action restores only the current session and does not remove the underlying regression.
For managed devices, BleepingComputer said on September 25, 2026, to deploy KB5124006 Known Issue Rollback on Windows 11 version 26H1 or KB5124010 Known Issue Rollback on versions 25H2 and 24H2. The cost is policy configuration plus a device restart, although the remainder of the installed update stays in place.
For broken File History, I would install an update released on or after September 22, 2026, including KB5124010, because Tech Insider identified those releases as the repair on September 24, 2026. I would then open File History and confirm that it can create or update a backup.
For Battlefield 6 or Wardogs, I would defer the optional KB5124010 preview while the crash reports remain unacknowledged, based on Neowin's September 25, 2026 account. The cost is postponing the fixes and changes that Notebookcheck documented on September 23, 2026, including Bluetooth, File Explorer, touchpad, and desktop-background work.
Frequently asked questions
Which Windows 11 versions have the black-screen problem?
Cybersecuritynews reported on September 25, 2026, that Windows 11 version 26H1 is affected through KB5120996, while versions 25H2 and 24H2 are affected through KB5120998.
Does the black-screen workaround remove the bad update?
No. Cybersecuritynews said on September 25, 2026, that starting explorer.exe restores desktop access for the session without eliminating the underlying update regression.
Is Windows Server listed as affected?
Cybersecuritynews reported on September 25, 2026, that no Windows Server platform was currently listed as affected by the desktop-loading incident.
Is KB5124010 a permanent fix for the black screen?
No. BleepingComputer said on September 25, 2026, that the KB5124010 Known Issue Rollback policy disables the problematic change on Windows 11 versions 25H2 and 24H2 until a future resolution ships.