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I'm trying to restart my X session and neither one of the methods I'm used to using are working on 11.10.

Is this a known bug?

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If you are having this kind of issue, you can reboot the computer from the command line:

sudo reboot

Make sure to save any work you may have open. This command will not prompt you at all, and programs which want to block shutdown will most likely be unable to do so. This will bypass X. If for some reason this does not work, try adding the "--force" option:

sudo reboot --force

If you are unable to launch a terminal, you may be able to get to run a command with Alt+F2, but be sure to use "gksu" or "kdesu" instead of "sudo". If this doesn't work, press Ctrl+Alt+F5 (you can use any F key from F1 through F6), login, and proceed as above (using "sudo", not "gksu"). If you still cannot reboot the machine, use the magic sysrq key

If you don't want to reboot the whole computer, you may be able to fix it by sending a SIGHUP to kdm (or gdm or lightdm), but it sounds as if you already tried that. But in case you haven't:

pgrep dm -l

Look at the PID's printed for

12345 kdm

(or gdm or lightdm), and then send it a signal:

sudo kill -SIGHUP 12345

(replace 12345 with whatever number it output)

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With the Kubuntu 11.10

Stopping the KDM with the command:

sudo stop kdm

Why stop kdm:

/etc/init.d/kdm stop:

Since the script you are attempting to invoke has been converted to an
Upstart job, you may also use the stop(8) utility, e.g. stop kdm


Log of sudo stop kdm 
Sat Oct 22 14:28:14 2011

kdm stop/waiting

Starting the KDM again with the command:

sudo start kdm


Log of sudo start kdm 
Sat Oct 22 14:28:45 2011

kdm start/running, process 1698


If the KDM is not running, stopping the KDM and trying to stop the KDM again:

Log of sudo stop kdm 
Sat Oct 22 14:31:12 2011

stop: Unknown instance: 
sudo died with exit status 1



man logsave
       logsave - save the output of a command in a logfile

       logsave [ -asv ] logfile cmd_prog [ ... ]

       The  logsave  program  will execute cmd_prog with the specified argument(s), 
       and save a copy of its output to logfile.


With the Karmic

Searching with the: "stop: Unknown instance" ->

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Kubuntu now uses lightdm, so simply do this:

sudo stop lightdm
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