What does Ctrl + Alt + F11 do and why can't I log into my account with Unity any more? [duplicate]

Solution 1:

Ctrl+Alt+F7 or Ctrl+Alt+F8 should find your GUI again.

The Ctrl+Alt+F# buttons bring up "TTYs" which are just terminal interfaces you can use without running gnome-terminal or another terminal program.

Solution 2:

Ctrl+Alt+F11 sort of puts the GUI to sleep, and puts you into a virtual terminal mode, something like the old fashion ttys.

Once in this mode you can choose between 6 different tty input screens. Each acting like it is an old-fashion tty. The different ttys can be chosen with Alt+F1 up to Alt+F7. Each of these virtual ttys will require that you log in with the old fashion Unix login that you would use from an old-fashion tty.

If you login to one of these and then try to restart the X-window server it won't let you because there is already a server running.

If you are in this virtual terminal mode you can use Alt+F1 through Alt+F6 to switch between the 6 different tty-like inputs. Each will look just the way you left it when you switched out. You can also use Alt+F7 to switch to the screen (not a tty) that is attached to the already running GUI.

Note there is a difference between Ctrl+Alt+ and just Alt+.

This mode is actually very useful if you are in something using full screen mode and you need access to a backend command shell.