This is seemingly caused by the virtualbox drivers not yet having support to non-root Xorg sessions.
The workaround for now is to install xserver-xorg-legacy and/or virtualbox-guest-dkms ** Package changed: xorg (Ubuntu) => xorg-server (Ubuntu) -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1525735 Title: X server fails to start under regular user in Xenial To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1525735/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : [email protected] Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
