I was running Ubuntu 18 and just now did the do-release-upgrade. I kept picking "Y" to install the maintainer's version of files assuming I could configure what was broken after it came up. It seemed to complete fine. I rebooted and it comes up, I can see the log messages, then the screen goes blank, but no desktop ever appears.
ssh is working and the contro-alt-F3 gets me to a prompt. I've tried all the various apt-get update, apt-get dust-upgrade, clean, auto remove, etc. that other topics suggest but it still doesn't give me a desktop.
My disks are not exported and they should be. I believe I had SMB set up because NFS wasn't stable when a Mac was a client (if I recall correctly). pi-hole seems to be up and working. That is about all that this critter is being used for.
This isn't a huge problem but I'm hoping it is something simple and worth the time to fix.