Microsoft patches Windows 11 Azure Virtual Desktop bug in Oct 13 update
The vendor patched a flaw causing desktop failures in virtual environments after August updates, marking the issue resolved on October 13.
Key points
- Microsoft resolved a bug causing black screens and Explorer crashes in Windows 11.
- The issue primarily affected Azure Virtual Desktop hosts using FSLogix profile loading.
- Fixes are included in cumulative updates released on October 13, 2026.
Microsoft has resolved a known issue that caused black screens and Windows Explorer crashes for users installing Windows 11 updates released since August. The vendor marked the problem as fixed on October 13, 2026, following the release of cumulative updates that address the desktop loading failures.
The defect prevented affected systems from automatically loading the desktop session after a user signed in. Instead, users encountered a black screen and had to manually start the desktop session to regain access. Application event logs on these systems also recorded Windows Explorer crashes, providing administrators with a clear indicator of the failure.
Context and Background
According to Microsoft’s Windows release health notice, the problem originated with the August 2026 non-security preview update, identified as KB5120996. That specific update carried OS Build 28000.2804 and affected Windows 11 version 26H1. The issue persisted through subsequent updates for that version until the resolution was deployed.
Microsoft states that the bug was resolved by Windows updates released on October 13, 2026, and by any updates released after that date. The company recommends that users install the latest available update for their device, as it contains important improvements and issue resolutions, including this specific fix.
Who Is Affected
This known issue mainly affects Azure Virtual Desktop (AVD) hosts that use FSLogix, a software solution designed to speed up user profile loading in virtual desktop environments. Some existing user profiles were more likely to fail to load the desktop compared to others. Microsoft lists Windows 11 versions 26H2, 26H1, 25H2, and 24H2 as the affected client platforms.
The vendor clarified that this issue does not affect Windows Server. Although reports primarily involved Azure Virtual Desktop environments using FSLogix, Microsoft did not describe every device running those Windows versions as affected. The problem was specific to certain configurations rather than a universal failure across all Windows 11 installations.
What should you do?
Users who have installed an update released on October 13, 2026, or later do not need to use any workaround for this issue. For those who cannot immediately install this month’s Windows updates, Microsoft provided a temporary workaround to restore access. This involves opening Task Manager by pressing Ctrl+Shift+Esc, selecting Run new task, entering explorer.exe, and clicking OK.
Enterprise administrators can mitigate the issue on managed devices using Known Issue Rollback (KIR) via Group Policy. For Windows 11 version 26H1, the relevant policy is KB5124006. For Windows 11 versions 25H2 and 24H2, the policy is KB5124010. Administrators must install and configure the policy matching their Windows version and then restart the devices to apply the setting. This Group Policy disables the change causing the issue until a resolution is released in a future Windows update.
What to do and how to stay safe: Microsoft
- Verify if your systems are running Windows 11 versions 24H2, 25H2, 26H1, or 26H2.
- Check application event logs for Windows Explorer crashes to identify affected endpoints.
- Deploy the October 13, 2026 cumulative updates to resolve the issue permanently.
- Apply the appropriate Known Issue Rollback Group Policy if immediate patching is not possible.
Step-by-step guide: Mobile Device Security: How to Protect Data Beyond Passwords
General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
Which Windows 11 versions are affected by this black screen bug?
Windows 11 versions 24H2, 25H2, 26H1, and 26H2 are listed as affected client platforms.
Does this issue affect Windows Server systems?
No, Microsoft clarified that this issue does not affect Windows Server.
How can I manually restart Windows Explorer if I am stuck on a black screen?
Open Task Manager with Ctrl+Shift+Esc, select Run new task, type explorer.exe, and click OK.
