Multiple issues with Workstation 16 and Windows 10 20H2

[myvmware13]

I've been running Workstation 16 for months without problems. Just recently installed the latest 20H2 update and it makes VMs slow to a crawl. Not only that, all of my snapshots are no longer valid because of CPU features are different.

The features supported by the processors in this machine are different from the features supported by the processors in the machine on which the virtual machine state was saved.

You may attempt to resume this virtual machine, but doing so may result in unpredictable behavior. Do you wish to resume this virtual machine?

Clicking Yes leads to a guest shutdown and this error message.

Feature 'misc.rsba_no' was absent, but must be present.

Module 'FeatureCompatLate' power on failed.

Failed to start the virtual machine.

If I disable side channel mitigations then the VMs will run (but not the snapshots because you have to shutdown the machine before changing the settings). But even with side channel disabled, the guests lag terribly to a point where it is sometime unusable.

The host does not have Hyper-V enabled.

Additionally, taking a new snapshot makes the entire system (host and guest) ground to a halt. It's not a memory, disk or CPU issue either because I never had these problems until installing 20H2.  Hopefully VMware is aware of these problems and will put out an update soon.

[ender_]

It may be possible that Hyper-V is still being used – if eg. VBS (virtualisation-based security) got enabled, that will enable Hyper-V. A quick way to test this is to try starting a VM with "Virtualize Intel VT-x/EPT or AMD-V/RVI" enabled – if Workstation complains that nested virt isn't supported, it's using Hyper-V (VMWare should really make it clearer when Hyper-V is being used on the host).

[continuum]

> Not only that, all of my snapshots are no longer valid because of CPU features are different.

NO - wrong conclusion !
Your suspended state is invalid - the snapshots may be fine.
So discard the suspended state - if you run into this problem.

To do that - edit the vmx-file and remove any line that references a .vmss file.
Also remove the vmss-file out of the VMs home directory.

Ulli