Windows bugs and fixes September 30 2026: status
Chapters
TL;DR
BleepingComputer reported on September 25, 2026, that recent Windows 11 updates caused black screens and stopped the desktop loading after sign-in. A permanent correction has not shipped, but affected users can launch Windows Explorer manually and managed devices can use Known Issue Rollback. Tech Insider reported on September 24, 2026, that the separate File History failure is resolved in updates released on and after September 22, 2026, including KB5124010.
- gHacks reported on September 27, 2026, that Windows 11 versions 24H2, 25H2, and 26H1 are affected.
- Cybersecuritynews reported on September 25, 2026, that Microsoft marked the desktop-loading incident as mitigated rather than permanently fixed.
- Tech Insider reported on September 24, 2026, that updates released on and after September 22, 2026, resolve the File History backup failure.
What broke on Windows 11?
Desktop loading broke after sign-in, gHacks reported on September 27, 2026.
According to BleepingComputer on September 25, 2026, an affected computer can show a black screen, withhold the usable desktop, and record Windows Explorer crashes in the application event log. The publication said the problem followed KB5120996 on Windows 11 26H1, KB5120998 on Windows 11 24H2 and 25H2, and subsequent updates including KB5124008 and KB5122880.
Cybersecuritynews reported on September 25, 2026, that Microsoft had primarily observed the Windows 11 bug on Azure Virtual Desktop hosts using FSLogix, especially when sessions loaded certain existing user profiles. The same report said a person may authenticate successfully without reaching a usable desktop because the Windows shell does not start automatically.
gHacks reported on September 27, 2026, that Microsoft opened the issue on September 24, marked it mitigated, and listed only Windows 11 client releases as affected. For continuity, see Windows bugs and fixes September 26 2026: black screen.
Has a permanent Windows update fix shipped?
No permanent correction has shipped, Cybersecuritynews reported on September 25, 2026.
gHacks reported on September 27, 2026, that Microsoft was developing a resolution for a future Windows update but had not supplied a release date or named the update. I therefore treat Microsoft’s mitigated status as confirmation that a workaround exists, not evidence that the underlying regression has disappeared.
Cybersecuritynews reported on September 25, 2026, that Microsoft issued KB5124006 260924_20071 Known Issue Rollback for Windows 11 26H1 and KB5124010 260924_20021 Known Issue Rollback for Windows 11 24H2 and 25H2. The publication said Known Issue Rollback reverses the problematic non-security change while preserving the rest of the installed update.
According to Cybersecuritynews on September 25, 2026, administrators must install the matching policy, configure it under Computer Configuration and Administrative Templates, and restart every affected endpoint. The cost is policy deployment, testing, and a restart, while the benefit is avoiding removal of the complete update.
Which Windows backup fix has shipped?
File History has a shipped fix, Tech Insider reported on September 24, 2026.
According to Tech Insider on September 24, 2026, the September 2026 security update KB5124008 left some customers unable to create or update File History backups. The publication said File History is the Control Panel feature that writes file backups to an external drive or network location.
Tech Insider reported on September 24, 2026, that Microsoft’s support documentation marked the failure resolved in updates released on and after September 22, 2026, including KB5124010. That shipped resolution is separate from the black-screen Known Issue Rollback package whose full name includes KB5124010 260924_20021.
I would verify that File History creates or updates a backup after installing the resolved update rather than relying only on the update history screen. Tech Insider’s September 24, 2026, account described the failure as quiet degradation rather than an outright crash for most affected users.
What can an affected person do today?
Launch Windows Explorer manually, BleepingComputer advised on September 25, 2026.
BleepingComputer reported on September 25, 2026, that an affected user can press Ctrl+Shift+Esc, select Run new task in Task Manager, enter explorer.exe, and select OK. The procedure starts the Windows shell and restores access without requiring removal of the installed update.
Cybersecuritynews reported on September 25, 2026, that the manual launch restores the desktop only for the affected session and does not remove the underlying regression. The workaround therefore costs another manual recovery whenever the shell fails to start in a later affected session.
For managed computers, Cybersecuritynews reported on September 25, 2026, that administrators should deploy the matching Known Issue Rollback policy and restart the device. For personal computers, gHacks reported on September 27, 2026, that Task Manager remains the available mitigation until Microsoft releases the permanent correction.
I would record the installed Windows 11 version and KB before choosing a rollback policy because Cybersecuritynews reported on September 25, 2026, that the packages differ between 26H1 and 24H2 or 25H2.
Frequently asked questions
Which Windows 11 versions have the black-screen problem?
gHacks reported on September 27, 2026, that Microsoft lists Windows 11 versions 24H2, 25H2, and 26H1 as affected.
Is this a Windows KB update problem on Windows Server?
gHacks reported on September 27, 2026, that server editions are not affected and that Microsoft’s affected-platform list covers Windows 11 client releases.
What do Microsoft’s Windows known issues say about 26H2?
Microsoft Learn listed desktop loading failures and domain trust failures as mitigated on September 29, 2026. Microsoft Learn said the domain problem can stop Credential Guard protected machine accounts signing in with valid domain credentials, while cached offline sign-in may continue working.
Should I remove the affected update to regain the desktop?
Cybersecuritynews reported on September 25, 2026, that users can regain the desktop by starting explorer.exe manually without removing the update. The publication said the procedure restores only the current session and leaves the regression unresolved.