January’s Patch Tuesday left many Windows Server administrators in dire straits: domain controllers in boot loops, ReFS volumes unavailable, and Hyper-V refusing to boot.
BeepComputer reports that administrators described domain controllers on all versions of Windows entering boot loops because the LSASS.exe process consumed all CPU resources and crashed the system, which automatically restarted.
He also notes that, at least on Windows Server 2012 R2, the Hyper-V hypervisor does not start, causing virtual machine launches to fail. It says that other unverified reports have reported the problem on newer versions of Windows Server.
The third issue is that Windows Resilient File System (ReFS) volumes are no longer accessible or are seen as RAW (unformatted) after installing updates. NTFS volumes are not affected.
So far, the only fix for these issues is to uninstall the entire update package, removing not only the fixes to the problem, but all included security updates as well.
Microsoft says it is aware of the issues and is investigating.
Update: BleepingComputer now reports that the company has pulled updates; these are KB5009624 for Windows Server 2012 R2, KB5009557 for Windows Server 2019, and KB5009555 for Windows Server 2022.
We’ll update this story when more information becomes available.