Microsoft Confirms Black Screens After Sign-In on Some Windows 11 Devices

Microsoft has acknowledged that recent Windows 11 updates have caused some devices to display a black screen after sign-in, with the desktop session failing to load.

The issue affects Windows 11 versions 24H2, 25H2, and 26H1, and started with the August 2026 non-security preview update, KB5120998.

According to Microsoft's Windows release health dashboard, the problem has been primarily observed on Azure Virtual Desktop hosts that use FSLogix for user profiles, and appears more often with existing user profiles.

To mitigate the issue, users can manually start Windows Explorer by hand using Task Manager, or IT administrators can install a Known Issue Rollback (KIR) Group Policy package to disable the change responsible for the problem.

Microsoft notes that it is working on a permanent fix and will release it in a future Windows update, but has not given a specific date or named the update that will carry the fix.