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I am running 12.04 LTS on a VM. I encountered a problem with the screen being black and the familiar orange background showing for a fraction of a second when clicking or resizing the screen. I had to shutdown the machine and now I have no GUI. I only get a black command-line interface.

As some other posts suggest, I attempted:

sudo service lightdm restart

This doesn't work for me because it gets stuck at this point:

Skipping profile in /etc/apparmor.d/disable: user.bin.firefox
Skipping profile in /etc/apparmor.d/disable: user.sbin.rsyslogd
* Starting AppArmor profiles                                        [ OK ]

Any ideas?

EDIT: /var/log/lightdm/lightdm.log:

[+0.00s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.2.1, UID=0 PID=933
[+0.00s] DEBUG: Loaded configuration from /etc/lightdm/lightdm.conf
[+0.00s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.00s] DEBUG: Registered seat module xlocal
[+0.00s] DEBUG: Registered seat module xremote
[+0.00s] DEBUG: Adding default seat
[+0.00s] DEBUG: Starting seat
[+0.00s] DEBUG: Starting new display for greeter
[+0.00s] DEBUG: Starting local X display
[+0.35s] DEBUG: X server :0 will replace Plymouth
[+0.44s] DEBUG: Using VT 7
[+0.44s] DEBUG: Activating VT 7
[+0.44s] DEBUG: Logging to /var/log/lightdm/x-0.log
[+0.64s] DEBUG: Writing X server authority to /var/run/lightdm/root/:0
[+0.64s] DEBUG: Launching X Server
[+0.65s] DEBUG: Launching process 960: /usr/bin/X :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch -background none
[+0.66s] DEBUG: Waiting for ready signal from X server :0
[+0.66s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.66s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+0.70s] DEBUG: Process 960 exited with return value 127
[+0.70s] DEBUG: X server stopped
[+0.70s] DEBUG: Removing X server authority /var/run/lightdm/root/:0
[+0.70s] DEBUG: Releasing VT 7
[+0.70s] DEBUG: Stopping Plymouth, X server failed to start
[+1.34s] DEBUG: Display server stopped
[+1.34s] DEBUG: Stopping display
[+1.34s] DEBUG: Display stopped
[+1.34s] DEBUG: Stopping X local seat, failed to start a display
[+1.34s] DEBUG: Stopping seat
[+1.34s] DEBUG: Seat stopped
[+1.34s] DEBUG: Required seat has stopped
[+1.34s] DEBUG: Stopping display manager
[+1.34s] DEBUG: Display manager stopped
[+1.34s] DEBUG: Stopping daemon
[+1.35s] DEBUG: Exiting with return value 1



share|improve this question
We need your lightdm log files, please post at least /var/log/lightdm/lightdm.log so we can see why no display is starting. The other logs in that directory may also be needed. – mfisch Nov 10 '12 at 21:23
Added logs as edit. – mdobrinin Nov 12 '12 at 16:38

Your lightdm log states that it can't start X and your x-0.log complains about a missing library. Try installing libxfont1, but I suspect you may be missing other stuff.

[+1.34s] DEBUG: Stopping X local seat, failed to start a display

/usr/bin/X: error while loading shared libraries: cannot open shared object file: No such file or directory

To install it:

sudo apt-get install libxfont1
share|improve this answer

I had this issue after enabling an experimental Nvidia driver. If you think you have the same issue:

  • on boot, type Ctrl-Alt-F1 to get command prompt.
  • to check if you have the nvidia module installed type lsmod | grep nvidia if there is output then you have nvidia installed, otherwise this is not a solution that will work for you
  • remove the nvidia module with sudo rmmod nvidia
  • restart lightdm with sudo service lightdm start
  • you should soon see the login screen. If you don't, then this solution can't help you.
  • for me, once I booted successfully, I had to remove all of the nvidia drivers through settings->additional drivers (I had all experimental additions installed). Otherwise when I restarted I would have the same problem and have to do the above every time
  • once I removed all the drivers, I rebooted and didn't have any issues. Then I enabled the default nvidia driver, restarted, and everything's good!
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