Microsoft's Windows 11 KB5124008 security update is breaking domain trust relationships on some enterprise systems, preventing users from logging in with valid domain credentials. The issue appears linked to the Windows Machine Identity Isolation security feature being set to enforcement mode after the update, causing machines to lose their secure channel with Active Directory. Administrators can restore access by disabling the feature and repairing the secure channel using PowerShell.
Microsoft's September 2024 Windows 11 update KB5124008, intended to restore popular features, is breaking multiple functionalities including WSL-based apps, Remote Desktop sessions, File History backups, and Claude Cowork's file access through a Plan9 filesystem issue. The mandatory patch was released days after Microsoft urged users to install updates immediately to prevent AI-assisted security exploits.