Comment 9 for bug 1500673

I, too, have this problem. No login screen after upgrade to 15.10 from 15.04.

I have now spent 36 hours trying to get this upgrade to work. I've tried everything I can find cruising the net. Nothing works. I've gone back and forth between gdm and lightdm. I've uninstalled and reinstalled ubuntu-desktop. All that nonsense and a lot more. I've restored file system backups to the original 15.04 and reapplied the update several times. Nothing in the syslog to suggest the problem.

At this point I give up. I'm going back to 15.04 and will stay there until somebody confirms a fix.

The real fix might just be that Canonical stops with these 6-month releases that don't work and goes to 1-year releases that do.