Comment 6 for bug 1234400

This seems to happen every time I install a raring update or upgrade, but I haven't updated often enough to swear to this. I can tell you that I had this problem twice, which is exactly 2 times more than I should have.

Basically, I get the login greeter screen, type in my password, it goes away for a couple of seconds, and then returns to the greeter screen without any visible error message. This is a serious WTF moment.

I was able to work around it (after a *lot* of scratching around and looking in /var/log/lightdm/ and elsewhere, which really didn't help much, and online searches, which did, eventually), as follows.

In desperation, I created a new user using a console (Ctrl-Alt-F1) session and usermod (lucky for me, I know a bit of sysadmin stuff). It was able to log in with no problems, of course. After getting a clue that .Xauthority was the likely culprit, I simply copied the new user's .Xauthority file over the one in my home directory.

This is not necessarily the best way to do it (probably deleting the file and running 'xauth generate :0 . trusted' is), but that's what got me over the hump.