A not-necessarily welcome addition to Ubuntu 11.10 (Oneiric Ocelot) is the inclusion of a guest account on the login screen. While only limited use of such an account would be permitted, some of us have no interest in offering this facility at all. Fortunately, as with many features of Linux systems, the guest account is configurable, i.e. can be disabled. You can achieve this as follows:
(1) In Terminal, issue the command: sudo gedit /etc/lightdm/lightdm.conf
(2) At the end of the section marked “[SeatDefaults]”, add the line:
(3) Save the file and reboot the computer
How do I disable the guest session?