Windows bugs and fixes September 29 2026: status
Chapters
What broke on Windows 11?
Windows Explorer failed after sign-in, leaving some Windows 11 sessions black, gHacks reported on September 27, 2026.
Affected users can authenticate without reaching a usable desktop, while Application event logs may record Windows Explorer crashes, Cybersecuritynews reported on September 25, 2026.
Microsoft has primarily observed the failure on Azure Virtual Desktop hosts using FSLogix, particularly when sessions load certain existing user profiles, BleepingComputer reported on September 25, 2026.
Server editions are not listed as affected, while client versions 24H2, 25H2, and 26H1 are listed, gHacks reported on September 27, 2026. My Windows bugs and fixes September 26 2026 report covered the same black-screen incident before gHacks confirmed on September 27, 2026, that a permanent correction still lacked a release date.
TL;DR
Windows Explorer failed to start after sign-in on some Windows 11 devices, leaving a black screen, Cybersecuritynews reported on September 25, 2026. A permanent fix has not shipped, but Microsoft offers manual Explorer recovery and Known Issue Rollback policies, gHacks reported on September 27, 2026.
- Microsoft marked the black-screen incident mitigated, not permanently fixed, Cybersecuritynews reported on September 25, 2026.
- The Windows 11 bug affects versions 24H2, 25H2, and 26H1, gHacks reported on September 27, 2026.
- Managed devices can use KB5124006 or KB5124010 Known Issue Rollback policies, BleepingComputer reported on September 25, 2026.
- The Windows update fix for File History shipped in updates released on and after September 22, 2026, Tech Insider reported on September 24, 2026.
Which Windows updates are implicated?
KB5120996 and KB5120998 introduced the regression for different Windows 11 versions, BleepingComputer reported on September 25, 2026.
For Windows 11 26H1, BleepingComputer on September 25, 2026, named the August 2026 preview update KB5120996 and the later Patch Tuesday update KB5124008 among affected updates.
For Windows 11 24H2 and 25H2, gHacks on September 27, 2026, identified KB5120998 as the originating August 2026 non-security preview update and said subsequent updates carried the problem forward.
BleepingComputer on September 25, 2026, also named KB5122880 among the later updates associated with the failure, but the cited reports do not provide a complete OS build for every affected release.
| Windows release | Originating update | Later named update | Source and date |
|---|---|---|---|
| Windows 11 26H1 | KB5120996 | KB5124008 | BleepingComputer, September 25, 2026 |
| Windows 11 25H2 | KB5120998 | KB5122880 | BleepingComputer, September 25, 2026 |
| Windows 11 24H2 | KB5120998 | KB5122880 | BleepingComputer, September 25, 2026 |
| Windows Server | Not listed as affected | Not listed as affected | gHacks, September 27, 2026 |
Which fixes have shipped?
File History has a shipped fix, but the black-screen regression does not, Tech Insider and gHacks reported in September 2026.
Tech Insider reported on September 24, 2026, that updates released on and after September 22, 2026, including KB5124010, resolved the File History failure triggered by KB5124008.
Neowin described KB5124010 on September 22, 2026, as a Windows 11 preview update for versions 25H2 and 24H2 with additional fixes and features.
The black-screen status is different because gHacks reported on September 27, 2026, that Microsoft had marked the Windows known issues entry mitigated while still developing a permanent resolution for a future update.
Microsoft had not named that future update or supplied its release date, according to gHacks on September 27, 2026, so no cumulative update can yet be presented as the permanent black-screen repair.
Who can act without waiting for IT?
Personal-PC users can launch Explorer, while administrators of managed devices can deploy the matching KIR, BleepingComputer reported on September 25, 2026.
A person at the keyboard can open Task Manager, choose Run new task, enter explorer.exe, and select OK, according to BleepingComputer on September 25, 2026.
That workaround restores desktop access temporarily rather than removing the update regression, and Cybersecuritynews reported on September 25, 2026, that recovery applies to the affected session.
IT departments still have a necessary role on enterprise-managed devices because BleepingComputer reported on September 25, 2026, that administrators must install and configure the appropriate Group Policy and restart every affected device.
Vendor release notes are actionable for ordinary users when the action is manual Explorer recovery, while the managed rollback properly remains with administrators, according to BleepingComputer on September 25, 2026.
What can a person do today?
Launch explorer.exe manually if sign-in ends at a black screen, BleepingComputer advised on September 25, 2026.
Press Ctrl+Shift+Esc, select Run new task, enter explorer.exe, and select OK, following the procedure BleepingComputer published on September 25, 2026.
The cost of that workaround is temporary recovery because it restores the desktop for the session without eliminating the underlying regression, Cybersecuritynews reported on September 25, 2026.
For Windows 11 26H1 under enterprise management, deploy KB5124006 Known Issue Rollback; for Windows 11 25H2 or 24H2, deploy KB5124010 Known Issue Rollback, according to BleepingComputer on September 25, 2026.
Install the matching policy, configure it under Computer Configuration > Administrative Templates, and restart the device, as gHacks instructed on September 27, 2026. Do not treat mitigation as a permanent repair because gHacks reported on September 27, 2026, that Microsoft had not named the update that will contain the final fix.
Frequently asked questions
Has Microsoft permanently fixed the Windows 11 black screen?
No. Microsoft marked the issue mitigated while developing a permanent fix for a future Windows update, gHacks reported on September 27, 2026.
Does uninstalling the affected update form part of Microsoft's workaround?
No cited workaround requires removal; Cybersecuritynews reported on September 25, 2026, that users can launch Explorer manually without uninstalling the update.
Which rollback policy applies to Windows 11 26H1?
KB5124006 Known Issue Rollback applies to Windows 11 26H1, BleepingComputer reported on September 25, 2026.
Is the File History failure still unfixed?
No. Updates released on and after September 22, 2026, including KB5124010, resolved it, Tech Insider reported on September 24, 2026.