Machine Identity Isolation

Microsoft issues workaround for domain login failures tied to Machine Identity Isolation bug

Microsoft confirmed that its September security updates (KB5124008 and KB5124012) for Windows 11 are causing domain authentication failures on enterprise systems that use the Machine Identity Isolation feature. Affected devices show domain trust and credential errors even when login details are correct, because the updates cause Windows to enforce existing Machine Identity Isolation settings that are only meant for environments running Windows Server 2025 domain controllers. The company has released a temporary workaround while it develops a permanent fix.

bleepingcomputer.com · 2026-09-17

Microsoft probes KB5124008 update for breaking Active Directory domain trust

Microsoft confirmed it is investigating reports that the Windows 11 KB5124008 security update is severing secure channel connections between domain-joined PCs and Active Directory after a reboot, locking out users with valid credentials. Administrators on Reddit and Microsoft's Q&A forums say the problem appears tied to the Windows Machine Identity Isolation feature when running in audit or enforcement mode, and that uninstalling the patch and repairing the domain trust restores access.

bleepingcomputer.com · 2026-09-16