Windows Server update causing bootloop domain controllers and Hyper V issue

Windows Server version updates cause spontaneous reboots and bootloops of domain controllers. In addition, Windows administrators report that Hyper-V no longer starts after applying a Windows Server update.

The problems occur in any case with Windows Server 2012 R2, Windows Server 2019 and Windows Server 2022, according to reports BornCity received and from posts on Reddit. The problems are said to have arisen after the release of updates KB5009624, KB5009557 and KB5009555 for the respective Windows Server versions.

The updates should address an issue where Active Directory attributes were not written correctly during an LDAP operation, but Windows administrators reported experiencing continuous reboots after committing. lsass crashes are suspected on Reddit. Lsass stands for Local Security Authority Subsystem Service and it manages the security policies on a system.

At the same time, there are reports that Hyper-V has stopped starting on Windows Server systems. The reports mainly concern Windows Server 2012 R2, according to Bleeping Computer, but new versions may also be affected. The site links to fixes for four Hyper-V vulnerabilities released this week. Finally, there are reports that ReFS volumes are no longer accessible after the updates are made. Uninstalling the updates would be a solution, but since they are cumulative updates, this also uninstalls security patches.