Comment 2 for bug 1290575

It appears that lightdm-gtk-greeter is waiting for init (upstart) to exit. upstart is in turn waiting on the indicator services to exit. From the log:

** (lightdm-gtk-greeter:2775): WARNING **: Failed to load user image: Failed to open file '/home/jack/.face': No such file or directory
init: indicator-power main process (2805) killed by TERM signal
init: indicator-power main process ended, respawning
init: indicator-sound main process (2807) killed by TERM signal
init: indicator-sound main process ended, respawning
init: indicator-power main process ended, respawning
init: indicator-power main process ended, respawning
init: indicator-power main process ended, respawning
init: indicator-power main process ended, respawning
init: indicator-power main process ended, respawning
init: indicator-power main process ended, respawning
init: indicator-power main process ended, respawning
init: indicator-power main process ended, respawning
init: indicator-power main process ended, respawning
init: indicator-power respawning too fast, stopped

From ps waxf:

 1939 ? Sl 0:01 /usr/sbin/lightdm-gtk-greeter
 1966 ? S 0:00 init --user --startup-event indicator-services-start
 2000 ? Ssl 0:00 \_ /usr/lib/x86_64-linux-gnu/indicator-sound/indicator-sound-service

(several such instances may be seen)