Windows server 2016 crashes after hot-plug CPU

[NJKwork]

When we first built our Windows 2016 template, we tested hot-add RAM and hot-plug vCPU.  Both worked and so we enabled it in the template.  However, today when we tried to hot-plug a CPU on a live server, it crashed.  I built a few test servers and it consistently crashes now whenever we hot-plug.

Now in full disclosure, our template have been updated many times - and I don't believe we test hot-plug after every change.  So I am pretty sure it is some change we recently made that caused it to break...including VMware hardware version 11.  I am pretty sure we have updated to 11 since the original template was developed.  I am betting that is the problem.

Has anyone else seen this problem and know the cause and/or solution to it?

Thanks

NK

[NJKwork]

I switched a test VM to hardware version 10, by editing the VMX file, but it still crashes when adding a 2nd vCPU.  But I am not sure if just editing the VMX file is a true 100% conversion back to an older hardware version.  Would I have to build a brand new VM at version 10 from scratch to truly test it?

NK

[RickVerstegen · Accepted solution]

If you created a snapshot or backup before the HW upgrade you can revert back otherwise you need to build a brand new one.

By the way, can you check if KB4284880 is installed within the guest OS?

There is a similar thread about this topic on technet:

Server 2016 Hot Add CPU in VMware gets BSOD "UNSUPPORTED PROCESSOR"

Rick

[NJKwork]

Yeah, I had just narrowed it down to either KB4338814 or KB4284880 and was going to report my findings here when I saw your post, which also mentioned KB4284880...so I think we have found the problem.  I will review the link you provided.

Thanks for the help.

NK