One fix usually breaks something else
Microsoft has resolved a previously reported issue that was causing blue screens and boot failures in Windows Server 2022 virtual machines (VMs) deployed on VMware ESXi hosts.
After installing last month’s KB5031364 cumulative update, Windows administrators first reported VM startup issues [1, 2, 3, 4, 5].
Days later, the company confirmed the issue, stating that it only affects guest VMs on VMware ESXi hosts equipped with an AMD Epyc physical processor, the “Expose IOMMU to guest OS” VMware option enabled, and Virtualization Based Security and System Guard Secure Launch enabled in Windows Server 2022.
The root cause has now been addressed, as Microsoft revealed during this month’s Patch Tuesday, with the release of the KB5032198 Windows Server 2022 cumulative update.
“This update addresses a known issue that affects virtual machines (VMs) that run on VMware ESXi hosts,” Redmond said.
“Windows Server 2022 might fail to start up. The affected VMs will receive an error with a blue screen and a stop code: PNP DETECTED FATAL ERROR.”
There are also temporary workarounds available:
Windows administrators who are unable to install the November 2023 Patch Tuesday updates immediately have temporary workarounds.
Toggling off “Expose IOMMU to guest OS” in the settings of the affected virtual machines is one approach. However, this workaround may only be viable for a limited set of systems, as certain environments require this option to be enabled by default.
As a last resort, uninstalling the problematic KB5031364 update can resolve the VM boot issues, but there is a significant drawback: this will also remove all security patches deployed with the update.
Microsoft released out-of-band Windows Server updates in January and December 2022 to address issues that were preventing Hyper-V VMs from booting and causing issues when creating new VMs on specific hosts.
Microsoft previously acknowledged a similar issue affecting VMware ESXi VMs with Secure Boot enabled following the installation of February 2023 cumulative updates.
Following that, VMware quickly issued emergency updates for vSphere ESXi to address the underlying cause of the VMs’ inability to find a bootable operating system.