Problem after upgrade from stretch to buster

After uppgrading from strech to buster in my virtual machine below Virtualbox my screen frozze in full-screen and I got the following error in /var/log/messages.

Jul 15 13:33:41 Inside gnome-shell[702]: Failed to set CRTC mode 1920x1200: Invalid argument

After lots of googeling I found the problem to be the video-memory. It was default set to 16Mb, after changing it to 32MB my machine started to work again 🙂