I had some problems installing VirtualBox on Linux Mint 20.3 Una. The USB devices weren't working. This Page was very helpful. You must add your account to vboxusers per the command below:

sudo usermod -aG vboxusers mir

Replace what's in RED with your account name. If you have successfully installed VB and your USB devices aren't working the command above may be all that's wrong.

Evolve and simplify!
Scott Bridgman, Why not join and post your own comments??
scott@muniac.com (email me)