I have install xubuntu 13.10 and i installed cinnamon 2.I loged out to test the new cinnamon instalation choosing the session i noticed that there is a session named "cairo" (cairo dock is installed too)and i tryied to login to see what it is but what i got was a black screen.the system is setup to autologing without asking a pass, so every time i reboot the system boots automaticaly to cairo session , which was the last session i tried to boot, and i allways get a black screen.Is there any way to change that????
As a temporary solution, you could log-in into a tty by pressing Ctrl+Alt+F6 and uninstall cairo-dock like this:
sudo apt-get remove cairo-dock
Then reboot, or reload lightdm (sudo service lightdm restart) and it should log to the default Desktop Environment, since the cairo session won't be installed.
When you finish, if you want to recover cairo-dock, just reinstall it:
sudo apt-get install cairo-dock