Bug from Windows Update causing VM to not boot

Question

I'm not sure of the best (and easiest) way to inform Microsoft about a potential bug with an update, so I'm hoping this post helps...

We have a Windows Server 2019 VM that won't boot after applying updates KB5050008 and KB5050182. I confirmed this by seeing that backups of the VM boot up prior to the install date of these updates, however backups immediately after the update date are unable to boot.

What happens during boot is that it goes to a blue screen with options to "Continue to Windows", "Troubleshoot" etc., however choosing the "Continue to Windows" option is NOT successful (it loops back to the same screen eventually). Booting to safe mode (with or without networking) DOES work. Additionally, I found that turning OFF the "Secure Boot" checkbox in the VM's settings (Hyper-V) allows the VM to boot up normally.

The Hyper-V host server is an HPE ProLiant DL385 Gen10 with an AMD EPYC 7302 CPU running Windows Server 2019.

One other interesting fact is that if we failover (via Hyper-V replication) to a different Windows Server 2019 Hyper-V host (Dell PowerEdge R740 with an Intel Xeon Gold 5118 CPU), the same VM boots up just fine (even with Secure Boot enabled), so it seems that the issue is also somewhat related to the underlying hardware.

The checkbox in the VM's settings to enable CPU compatibility is normally off, however enabling it does not resolve the issue.

Lastly, the Hyper-V host server that experiences/causes the issue records the following event log when the issue occurs:

Source: Hyper-V-Worker

Event ID: 18560

Level: Critical

Message (partially redacted):

'<VMNAME>' was reset because an unrecoverable error occurred on a virtual processor that caused a triple fault. If the problem persists, contact Product Support. (Virtual machine ID <VM ID>)

This Hyper-V host server has been fully updated (both Windows and HPE updates) and rebooted.

Answer 1

Hi Greg Caravelli,

Thanks for your sharing. I think end user that experienced similar issues will benefit a lot from your sharing. Many features of our current products are designed and upgraded based on customer feedback. We strive to capture any negative reviews in order to ensure that we are continuously improving our products to meet our customers' needs. With your efforts, we are committed to improving our products. Also, I found the following article that might be helpful, just for your reference and hope it helps.

Known issues in this update

Troubleshoot Windows VM OS boot failure - Virtual Machines | Microsoft Learn

Best Regards,

Ian Xue

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