try to delete your .ufoai/2.2 dir - in your home dir also try to start in none-fullscreen mode via ./ufo +set vid_fullscreen 0 you can also try to start ufo via gdb (debugger) and cancel the execution to see where ufo stop responding built as followed http://ufoai.ninex.info/wiki/index.php/Debian gdb ufo run +set vid_fullscreen 0 +set vid_grabmouse 0 switch back to gdb - hit ctrl+c type bt full to gdb console