I've just installed ubuntu desktop 20.04 on my virtual box on macOS 10.14.6
I installed the guest additions too and restarted.
If I try resizing the window to be smaller it seems that the resolution is updated correctly, if I resize the window to bigger the ubuntu display becomes all black
if I hit cmd+f the VM goes full screen, but the resolution doesn't change from the one in the window. So it remains black if it was a big window, or tiny if it was a small window.
Any ideas on what to do?
Best Answer
One thing to consider here is that Ubuntu V20 is very new and Virtual Box may need an upgrade to keep up.
Use the older but LTS version of Ubuntu and that should be able to work for you.