# sudo vim /etc/lightdm/lightdm.conf
[SeatDefaults]
greeter-session=unity-greeter
user-session=ubuntu
# add this to disable guest session
allow-guest=false
# sudo vim /etc/lightdm/lightdm.conf
[SeatDefaults]
greeter-session=unity-greeter
user-session=ubuntu
# add this to disable guest session
allow-guest=false