Virtualbox enable nested vtx/amd-v greyed out

Question

On my Ubuntu 18.04, I\'ve installed VirtualBox 6.0 in order to have nested virtualization. Virtualization is

Answer 1

It turned out it was greyed out for a reason! I have Windows 10 host and I used Docker for some time and uninstalled but it kept Hyper-V technology enabled (Which is incompatible with virtualization).

DO NOT DO ON A SERVER | THIS WILL DISABLE Hyper-V Technology - USE AT YOUR OWN RISK

Open command prompt as admin and run the following then restart your PC

DISM /Online /Disable-Feature:Microsoft-Hyper-V

PowerShell Disable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-Hypervisor -All

bcdedit /set hypervisorlaunchtype off