http://www.ubuntugeek.com/fix-for-cant-login-after-upgrading-from-ubuntu-13-04-to-ubuntu-13-10.html

I had the same problem and found a thread elsewhere that solved the problem in a different way.

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As above, at the login screen use Cntrl+Alt+F1 to open a terminal window and login at the command line instead

by default you should be in your home directory,
use the command ‘pwd’ to show what directory you are in, in my case…
pwd
/home/peter

if you are not in your home directory change to it using
cd /home/’username’

here you need to remove two files (note the ‘.’ prefix on both) .Xauthority and .ICEauthority

to show the files type the commands
ls .Xauthority -hal
ls .ICEauthority -hal

Assuming they are there the command to remove them is…
rm .Xauthority .ICEauthority

then reboot the machine using
sudo shutdown -r now

After reboot I was able to login as normal

http://czmmiao.iteye.com/blog/1003810

chown $USER:$USER -R /home/$USER/

 chmod 644 /home/$USER/.ICEauthority

文章题目：xubuntu无法进图形界面问题-创新互联
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