On Windows 10 I recently ran into the following error message that prevented me from running any of my VMs:
After removing the Hyper-V Role in Windows features, the problem still persisted. I turned out that it was due to
Windows Defender Credential Guard and virtualization-based security.
Microsoft Windows Defender Credential Guard is a security feature that isolates users' login information from the rest of the operating system to prevent theft.
Good exlaination here:
The solution was to go for the following: