How to turn off guest account in Ubuntu 12.04
After the installation of Ubuntu 12.04 LTS (Precise Pangolin) I have noticed that Canonical - unfortunately - hadn't given up the opportunity of loging on guest account introduced in Ubuntu 11.10 (Oneiric Ocelot).
The first thing I have done was to turn off this option, as I don't like the idea that any person without credential could log into my system.
Fortunately it can be done within few seconds.
Open terminal (ctrl+t) and execute following command:
sudo gedit /etc/lightdm/lightdm.conf
Original content of lightdm.conf file should looks like this:
[SeatDefaults] user-session=ubuntu greeter-session=unity-greeter
Enter: allow-guest=false to SeatDefaults section. Modified content should looks like below:
[SeatDefaults] user-session=ubuntu greeter-session=unity-greeter allow-guest=false
Press ctrl+s to save. Now, you just have to restart your system to see the logon screen without guest account.