I recently upgraded my system from Debian testing to Unstable. After, upgrading i'm not able to login to my system. Instead of a login screen an error page showing the text,
"Oh no! Something has gone wrong
A problem has occured and system can't recover
Please log out and try again"
is displayed with a logout button below.
Although i could login to a virtual console and launch Gnome desktop by issuing startx command.