Unsurprisingly this appears to have been a VirtualBox issue, not a Linux Mint issue.swordfish wrote:I'm running LMDE under VirtualBox and it reports being unable to load VirtualBox Guest Additions. StartX says it can't start because a server is already running and suggests deleting /tmp/.X0-lock, which does not appear to exist.
After reinstalling VirtualBox Guest Additions, I am up and running again.