LightDM doesn't start automatically.

[Splooshie123]

When I booted into Ubuntu, it got stuck at the splash screen. However, I was able to the console, meaning the system had started, but lightdm had not. Had I not started lightdm manually from the console, it would have been stuck at the splash screen forever.

This is my /var/log/boot.log:

fsck from util-linux 2.20.1 
Ubuntu: clean, 379898/6553600 files, 10754588/26214400 blocks 
modem-manager[1093]: <info>  ModemManager (version 0.5.2.0) starting... 
  
modem-manager[1093]: <info>  Loaded plugin Sierra 
  
modem-manager[1093]: <info>  Loaded plugin Linktop 
  
modem-manager[1093]: <info>  Loaded plugin MotoC 
  
modem-manager[1093]: <info>  Loaded plugin Novatel 
  
modem-manager[1093]: <info>  Loaded plugin Samsung 
  
modem-manager[1093]: <info>  Loaded plugin Option 
  
modem-manager[1093]: <info>  Loaded plugin Option High-Speed 
  
modem-manager[1093]: <info>  Loaded plugin X22X 
  
modem-manager[1093]: <info>  Loaded plugin Generic 
  
modem-manager[1093]: <info>  Loaded plugin Ericsson MBM 
  
modem-manager[1093]: <info>  Loaded plugin Longcheer 
  
modem-manager[1093]: <info>  Loaded plugin Huawei 
  
modem-manager[1093]: <info>  Loaded plugin ZTE 
  
modem-manager[1093]: <info>  Loaded plugin Wavecom 
  
modem-manager[1093]: <info>  Loaded plugin Gobi 
  
modem-manager[1093]: <info>  Loaded plugin SimTech 
  
modem-manager[1093]: <info>  Loaded plugin Nokia 
  
modem-manager[1093]: <info>  Loaded plugin AnyData 
  
Skipping profile in /etc/apparmor.d/disable: usr.bin.firefox 
Skipping profile in /etc/apparmor.d/disable: usr.sbin.rsyslogd 
 * Starting mDNS/DNS-SD daemon[ OK ] 
 * Stopping Mount filesystems on boot[ OK ] 
 * Starting AppArmor profiles         [ OK ] 
Rather than invoking init scripts through /etc/init.d, use the service(8) 
utility, e.g. service S20lightdm start 
 * Stopping System V initialisation compatibility[ OK ] 
 * Starting System V runlevel compatibility[ OK ] 
 * Starting automatic crash report generation[ OK ] 
 * Starting restore sound card(s') mixer state(s)[ OK ] 
 * Starting ACPI daemon[ OK ] 
 * Starting save kernel messages[ OK ] 
 * Starting anac(h)ronistic cron[ OK ] 
initctl: Unknown job: S20lightdm 
 
Since the script you are attempting to invoke has been converted to an 
Upstart job, you may also use the start(8) utility, e.g. start S20lightdm 
 * Starting CPU interrupts balancing daemon[ OK ] 
 * Starting crash report submission daemon[ OK ] 
speech-dispatcher disabled; edit /etc/default/speech-dispatcher 
 * Starting deferred execution scheduler[ OK ] 
 * Starting regular background program processing daemon[ OK ] 
 * Starting VirtualBox kernel modules         [ OK ] 
 * Stopping anac(h)ronistic cron[ OK ] 
 * Stopping save kernel messages[ OK ] 
 * Stopping restore sound card(s') mixer state(s)[ OK ] 
 * Starting the Winbind daemon winbind         [ OK ] 
saned disabled; edit /etc/default/saned 
 * Stopping cold plug devices[ OK ] 
 * Stopping log initial device creation[ OK ] 
 * Starting load fallback graphics devices[ OK ] 
 * Starting configure virtual network devices[ OK ] 
 * Stopping load fallback graphics devices[ OK ] 
 * Stopping configure virtual network devices[ OK ] 
 * Starting configure network device security[ OK ] 
 * Starting GNOME Display Manager[ OK ] 
 * Starting Userspace bootsplash[ OK ] 
 * Starting anac(h)ronistic cron[ OK ] 
 * Stopping anac(h)ronistic cron[ OK ] 
 * Stopping GNOME Display Manager[ OK ] 
 * Starting LightDM Display Manager[ OK ] 
 * Stopping LightDM Display Manager[ OK ] 
 * Stopping Userspace bootsplash[ OK ] 
 * Checking battery state...         [ OK ] 
 * Stopping System V runlevel compatibility[ OK ] 
 * Starting CUPS printing spooler/server[ OK ] 
 * Starting Mount network filesystems[ OK ] 
 * Stopping Mount network filesystems[ OK ]

The bold messages show lightdm starting but then stopping again. After that is says it's stopping the splash screen, which never happens.

Any ideas?

Don't remember why I looked, but I found out that all the lightdm scripts in /etc/rc*.d have the K20 prefix (which means "disabled", apparently). Maybe this has something to do with it?

[Splooshie123]

Fixed it. I installed GDM a few days ago and after removing it, /etc/X11/default-display-manager contained lightdm instead of /usr/sbin/lightdm.

[dcstar]

Fixed it. I installed GDM a few days ago and after removing it, /etc/X11/default-display-manager contained lightdm instead of /usr/sbin/lightdm.

Then report it as a bug or it may never get fixed.

[hussam_nasir]

This worked for me too. Please do report this a a bug . Only then will this be resolved.

[Cavsfan]

Fixed it. I installed GDM a few days ago and after removing it, /etc/X11/default-display-manager contained lightdm instead of /usr/sbin/lightdm.

I guess it is still not fixed.
This saved me too!
I installed gdm on Precise and almost lost the ability to get back into it.
Found where sudo dpkg-reconfigure lightdm would make lightdm work except it didn't.
Since recovery is to a read only file system I could not do anything there until I found something Paddy Landau had posted on a bug about it.
He said this was a workaround and it worked:
Login to recovery and then enter:

mount --options remount,rw /
mount --all

So, then I was successfully able to enter sudo dpkg-reconfigure lightdm without getting an error. I also purged gdm.
But, upon bootup all it would do was have a black screen with 4 dots that turned yellow and would not go past that.
I discovered I could press ALT+F2 and get the login prompt. Then I could enter sudo service lightdm start and it would finally allow me to login to Precise normally.
I knew that lightdm was there but, wasn't starting upon bootup.
That is when I found this thread.
Editing /etc/X11/default-display-manager saved me! Whew!
Thank you Splooshie123!

[Lennaron]

Thank you, helped a lot after some months with starting lightdm by alternate console

[firekage]

Heh, i have to admit that i didn't know about this, and the cause of this. It happened to me also - i installed, just like you, gdm, and after that i could not start lightdm even when gdm was purged, also my system, if i was succesful in starting lightdm, was started in low graphic mode - don't know why.

[Cavsfan]

Heh, i have to admit that i didn't know about this, and the cause of this. It happened to me also - i installed, just like you, gdm, and after that i could not start lightdm even when gdm was purged, also my system, if i was succesful in starting lightdm, was started in low graphic mode - don't know why.

Did you edit /etc/X11/default-display-manager?

gksudo gedit /etc/X11/default-display-manager
and make sure it contained /usr/sbin/lightdm and not just lightdm?

If it gives you read only access enter:

mount --options remount,rw /
mount --all

before hand. I had to write this stuff down when I did it.

[firekage]

Did you edit /etc/X11/default-display-manager?

gksudo gedit /etc/X11/default-display-manager
and make sure it contained /usr/sbin/lightdm and not just lightdm?

If it gives you read only access enter:

mount --options remount,rw /
mount --all

before hand. I had to write this stuff down when I did it.

No, i just reinstalled gdm and i've been using it because i didn't know why lightdm doesen;t want to work at all.

Now i know. Thanks.

[henriquev162]

Hello guys, please help me I'm having the same problem but my /etc/X11/default-display-manager have this line /usr/sbin/lightdm and my lightdm stills not starting automatically... I haven't installed GDM, I think this started to happen after my qShutdown installation...