10.10 Update to 4.6 Breaks KDM - Can't Login

[Jackie McGhee]

After upgrading to KDE SC 4.6 via kubuntu-backports (as outlined at http://www.kdedevelopers.org/node/4378). It seemed to me that everything downloaded and installed correctly, except at the end a window opened telling me that I should manually intervene for an issue surrounding /etc/kde4/kdmrc and /etc/kde4/kdmrc.dpkg-dist.

I went with the original and upon reboot I see the KDM screen (nice new background) but in the sessions menu, there is only Default and Failsafe - no KDE entry. Both Default and Failsafe fail to login. No splash is visible, the screen flickers for a second and then I get the X cursor and it's back to the KDM login screen.

I switched to a console and upon login, I get a message that there has been a "Fatal Server Error", that there is already a server running on display 0 and that I should remove /tmp/.X0.lock to proceed. I tried this, rebooted and had the same result.

I switched to a console again, logged in and saw the same messages about the fatal server error, .X0.lock and so on so I backed up the original kdmrc to kdmrc.OLD and renamed kdmrc.dpkg-dist to kdmrc, deleted /tmp/.X0.lock and rebooted. The same issue repeated when trying to log in: flicker, X cursor and back to KDM.

I've searched the web and Ubuntu forums in particular and while I see issues surrounding the .X0.lock file, none of those instances mirror my own, but my search-fu might just be weak.

I should point out that I am very inexperienced with KDE. Prior to 4.5 I had always used Gnome and have never come across this before (with GDM) so I'm a little out of my depth. It's also worth saying that this happened on another machine running Ubuntu 10.04 back when 4.5 was in kubuntu-backports but as that was an Ubuntu machine I had 'added' kubuntu-desktop to, I thought it was just because of the route I had taken. This instance, however, is on a clean install of Kubuntu 10.10.

If there is any further information required, let me know what I need to do to get it to you.

[Jackie McGhee (jackiemcghee-deactivatedaccount)]

More digging around found an earlier report of the same issue (https://bugs.launchpad.net/ubuntu/+bug/708151).

My bad.