Hyper-V Still Around, Windows Server Updates started again

Microsoft has gotten a grip on the first problems reported after the patch day in January. The group has restarted the distribution of security updates for Windows Server after the updates were withdrawn for a short time. Windows Server January 2022 Cumulative Updates are now available again through Windows Update. As we had reported, Microsoft had withdrawn the updates, but without commenting on the facts. The main focus is on the updates KB5009624 for Windows Server 2012 R2, KB5009557 for Windows Server 2019 and KB5009555 for Windows Server 2022.

After Windows administrators installed the updates, some found that their Windows servers got stuck in boot loops, ReFS volumes became inaccessible and Hyper-V would no longer start. After the numerous problems reported by Windows administrators in the first few days after patch day, the updates were suddenly no longer available via Windows Update on Thursday. However, anyone who wanted to could still download and install them via Windows Server Update Services (WSUS) and the Microsoft catalogue. Those affected had reported that they could no longer start the Hyper-V host after the security updates, with the error message only stating that the hypervisor was not running (“The virtual machine could not be started because the hypervisor is not running”).

Identified issues in the updates

Virtual machines are completely knocked out with this. Now the updates are all available again via Windows Update. However, the Windows team calls in the Support articles in the Knowledge Base no details on why they first stopped the update and then put it back into distribution. However, there is now a note in the “Known issues in this update” section. There it says:

Monthly Rollup KB5009586 Windows Server 2012

“After installing this update on a device using Unified Extensible Firmware Interface (UEFI), Hyper-V virtual machines (VMs) may not start. We are currently checking for an update and will provide an update in an upcoming release.”

Microsoft has therefore decided to redistribute the update and investigate the error in parallel. This suggests that this is just an isolated issue. A bugfix update has been announced, but when it’s coming is uncertain.