Microsoft Confirms Windows 11 Updates Cause Black Screens After Sign-In

Microsoft has confirmed that recent Windows 11 updates can leave devices on a black screen after sign-in, with the desktop session failing to load. The issue affects versions 24H2, 25H2, and 26H1, started with the August 2026 KB5120998 update, and is mostly seen on Azure Virtual Desktop hosts using FSLogix.

• Affects Windows 11 24H2, 25H2, and 26H1; server editions are not affected
• Issue began with the August 2026 non-security update KB5120998
• Mostly observed on Azure Virtual Desktop hosts using FSLogix profiles
• Workaround: manually start explorer.exe via Task Manager