- Login to a text-only terminal by pressing Ctrl+Alt+F1 (or F2..F6). This is assuming the keyboard is still responding.
- Run top at command prompt. You will see all your application programs running happily in the status shown. You need to kill compiz. That's the name of the program for Unity shell.
- Press 'k'. Enter PID for compiz. Press Enter. And then Enter again for the second time to accept the default kill signal  to send to compiz. That's it! You can logoff from terminal.
- Get back to X-Windows GUI by pressing Ctrl+Alt+F7. You shall see the GUI applications again. In a few seconds, the system will revive compiz and you shall see the Unity UI consisting of the app launch bar, the Dash, etc.
Thursday, July 26, 2012
Recover non-responsive frozen Unity desktop GUI
Apparently the new Unity based desktop environment introduced in Ubuntu 12.04 has some stability issues to sort out. Once in a while, the GUI becomes non-responsive. Mouse pointer is alive, so is the keyboard CAPS lock kind of keys that give LED indications. Just that nothing happens on the UI. It's frozen. So, what do you do? Kind of obvious for some, but still...