(Re)installing ubuntu-gnome-default-settings and then running "sudo dpkg-reconfigure gdm" to switch back to gdm (from lightdm) worked for me.
This is a nasty, renders-system-unusable bug though and it should not be de-prioritized just because there's a workaround that worked for 2 users. -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gdm in Ubuntu. https://bugs.launchpad.net/bugs/1500673 Title: gdm unusable after upgrading to 15.10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm/+bug/1500673/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
