Windows bugs and fixes September 28 2026: status

What broke on Windows 11?

The main break is a black screen after sign-in, Cybersecuritynews said on September 25, 2026.

According to BleepingComputer on September 25, 2026, the problem mainly affects Azure Virtual Desktop hosts using FSLogix and can prevent an authenticated user from reaching a usable desktop. Cybersecuritynews said on September 25, 2026 that Windows Application event logs may record Windows Explorer crashes when the shell fails to start automatically for an existing user profile.

Finance Biggo said on September 28, 2026 that Microsoft traced the trigger to the preview update released on August 27 and observed the highest incidence with FSLogix on Azure Virtual Desktop hosts. BleepingComputer said on September 25, 2026 that affected updates include KB5120996 for Windows 11 26H1, KB5120998 for Windows 11 24H2 and 25H2, and subsequent updates KB5124008 and KB5122880.

I treat the black screen as a documented Windows 11 bug rather than an unexplained help desk symptom because Microsoft has published the affected updates, symptoms, workaround and KIR packages, according to BleepingComputer on September 25, 2026. The earlier progression is covered in Windows bugs and fixes September 26 2026: black screen.

Has Microsoft shipped a permanent black-screen fix?

No. BleepingComputer said on September 25, 2026 that no permanent fix was available.

Cybersecuritynews said on September 25, 2026 that Microsoft lists the incident as mitigated while engineers continue developing a permanent correction for a future Windows update. A mitigation reduces the immediate failure, but it does not remove the underlying regression from the affected update, according to Cybersecuritynews on September 25, 2026.

BleepingComputer said on September 25, 2026 that Microsoft supplied KB5124006 Known Issue Rollback for enterprise-managed Windows 11 26H1 devices and KB5124010 Known Issue Rollback for Windows 11 25H2 and 24H2 devices. Microsoft said through BleepingComputer on September 25, 2026 that administrators must install and configure the matching Group Policy and restart each device before the setting takes effect.

I would not describe KIR as the finished Windows update fix because BleepingComputer said on September 25, 2026 that the policy disables the offending change only until a resolution arrives in a future Windows update. Finance Biggo said on September 28, 2026 that KIR rolls back only the specific change causing the problem, preserving the rest of the installed update.

Which separate Windows fixes have shipped?

KB5124010 fixes File History, Tech Insider said on September 24, 2026.

Tech Insider said on September 24, 2026 that KB5124008 could prevent File History from creating or updating backups, while updates released on and after September 22, 2026 resolve the failure. That account names KB5124010 as an update containing the correction, and my September 24 File History report covers the earlier status.

Notebookcheck said on September 23, 2026 that KB5124010 also fixes a 0x139 blue-screen crash during Bluetooth audio streaming and a Bluetooth toggle that could remain on when the radio was off. Notebookcheck said on September 23, 2026 that the update improves cloud-file thumbnail reliability and prevents a click near the File Explorer address bar from erasing typed text.

Neowin said on September 22, 2026 that KB5124010 is a Windows 11 preview update for versions 25H2 and 24H2, with many additions rolling out gradually. KB5124010 therefore names both a preview update and, in Microsoft’s black-screen guidance, a Known Issue Rollback policy for Windows 11 25H2 and 24H2, according to Neowin on September 22, 2026 and BleepingComputer on September 25, 2026.

What can a person at the keyboard do today?

Launch explorer.exe through Task Manager, BleepingComputer said on September 25, 2026.

BleepingComputer said on September 25, 2026 to press Ctrl+Shift+Esc, select Run new task, enter explorer.exe, and select OK when the black screen appears after sign-in. Cybersecuritynews said on September 25, 2026 that the procedure starts the Windows shell and restores desktop access for the current session.

The cost of the manual workaround is that it does not eliminate the update regression and may need to be used when an affected session fails again, according to Cybersecuritynews on September 25, 2026. For enterprise-managed devices, BleepingComputer said on September 25, 2026 that IT administrators should install the matching KB5124006 or KB5124010 KIR policy, configure its Group Policy and restart the device.

On a managed Azure Virtual Desktop host, IT administrators can install and configure the matching KIR Group Policy and restart the device, according to BleepingComputer on September 25, 2026. Ordinary users can still act on Microsoft’s published workaround by starting Explorer manually, while anyone relying on File History can install an update released on or after September 22, 2026, including KB5124010, according to Tech Insider on September 24, 2026.

A permanent correction for the black-screen regression remains unknown, and Cybersecuritynews said on September 25, 2026 only that Microsoft plans to deliver it through a future Windows update.