On Windows 10 I recently ran into the following error message that prevented me from running any of my VMs:
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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:
https://searchenterprisedesktop.techtarget.com/definition/Microsoft-Windows-Defender-Credential-Guard
The solution was to go for the following:
https://docs.microsoft.com/en-us/windows/security/identity-protection/credential-guard/credential-guard-manage#disable-windows-defender-credential-guard