Ubuntu 12.04 does not start x after boot up. Worked until now without any problem, and last shutdown was clean.

After text log in I can run startx, but no tray and Alt+Tab does not working.

Command startx run my default gnome classic and gnome statup scripts also runs.

How to restore to start X automatically?

1 Answer 1


After boot,try to start desktop manager:

 sudo service lightdm start

then check if lightdm is default desktop manager:

 cat /etc/X11/default-display-manager

if not, edit file with:

/usr/sbin/lightdm (or /usr/bin/lightdm)

Reboot and lightdm should start.

  • After boot up the command sudo service lightdm start start up my X as expected with panels and all customization working. File /etc/X11/default-display-manager contains /usr/sbin/lightdm, needed not to change anything. The executable file exist in that folder. After reboot X does not start automatically, still requires to manually sudo service lightdm start. How to make lightdm service to start automatically ?
    – fsh
    Commented Jun 1, 2013 at 13:19
  • 1
    try to reconfigure package: sudo dpkg-reconfigure lightdm. If not working, try to delay startup of lightdm: in /etc/init/lightdm.conf before command exec lightdm add sleep 2 (or more). It seems to be a issue related of use of SSD.
    – girardengo
    Commented Jun 1, 2013 at 14:51

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