VM does not start with Windows feature enabled: Virtual Machine Platform

[fe3]

Host Windows 11
VirtualBox 6.1.34

My Ubuntu guest did not start on my Windows host or was very slow and no smooth operation was possible. On an identical computer it worked without problems.

The reason was the installed Windows feature: Virtual Machine Platform.

After disabling this feature, I was able to start the guest without problems.

Is this a known problem?

[mpack]

HMR3Init: Attempting fall back to NEM (Hyper-V is active).