[20.04] Workaround for Xorg crashes to Login prompt in Virtual Machines

Currently there is a bug in 20.04 that causes the desktop xorg session to crash and drop the user back to the GUI Login screen.

This bug occurs with several programs and is not limited to Ubuntu MATE. However, it is particularly troublesome for us as Welcome is one of the programs that this issue affects. It is possible for a user running Ubuntu MATE 20.04 in a Virtual Machine to come upon a login-crash loop.

While this is being worked out, there are a couple of workarounds.

  1. On the first boot after installation, before logging into the machine, drop into a TTY session login and remove the gstreamer-vaapi application. Then the user can login to the machine and not have the possibility of this particular login crash loop.

    At the GUI Login screen:

    1. Ctrl + Alt + F1 to enter a TTY.

    2. Login with your username and password and do the following:

      sudo apt-get purge gstreamer1.0-vaapi
      sudo apt-get autoremove --purge
    3. Ctrl + Alt + F7 will bring you back to the GUI Login and you can proceed as you would normally.

  2. If using KVM or QEMU Virtual Machines please use 'virtio' as your video adapter
    If using Virtual Box please use VMVGA as your video adapter.


I installed Ubuntu Mate 20.04.1 on my SSD a couple of days ago and every time I boot up I get a black screen with the mouse cursor. Only way to show the desktop is by CTRL + ALT to a TTY and changing back to the desktop with Ctrl + Alt + F7. That fixes it.

Is mine related to this one or is it different?