I'm using Zorin. Only switching to the Greek layout causes this problem. Before, it would crash and let me log in again without the Greek layout being enabled. Now I get "Oh no! Something has gone wrong." every time I log in. Switching the keyboard layout in the log in screen doesn't matter because it doesn't affect what happens past the log in screen.
I'm looking at /etc/default/keyboard currently using recovery mode. I tried changing "XKBLAYOUT=us,us,gr" to "XKBLAYOUT=us,us", but that didn't work.