System Settings/Input Devices
Keyboard
Enable Control + Alt + Backspace to kill X-Server
Under the
, make sure "Configure keyboard options" is checked. Then look in the list below for "Key sequence to kill the X server". Under it, you should be able to check "Control + Alt + Backspace". Once done, click on Apply.![](/images.userbase/thumb/0/07/Enable_Ctrl_%2B_Alt_%2B_Backspace_to_kill_X-Server.png/350px-Enable_Ctrl_%2B_Alt_%2B_Backspace_to_kill_X-Server.png)