On September 24, Microsoft reported an issue affecting devices that installed the August 27 preview update for Windows 11, causing a black screen after sign-in and preventing the desktop from loading correctly. This issue primarily impacts Azure Virtual Desktop (AVD) hosts using FSLogix with existing user profiles. The affected OS versions are Windows 11 versions 26H1, 25H2, and 24H2, and the causal update is KB5120998. Microsoft has issued interim workarounds, including a manual desktop launch and a Known Issue Rollback (KIR), which will be automatically delivered to non-enterprise devices. Affected enterprise-managed devices require manual deployment of the KIR policy. The black screen issue is part of a series of update-related problems for Windows 11 in 2026, while Windows 10 has experienced fewer issues during the same timeframe.