Kubuntu KDE 4.5 Upgrade Problem and solution

So I just did an dist-upgrade of my Kubuntu 10.04 system running KDE 4.4 to KDE 4.5. Upon a reboot, there was a problem. I had no desktop. Just a blank black screen.

So I began to dig around to see what the problem was.

SOLUTION
The solution was to install the package 'kubuntu-desktop' which triggered a group other packages to be installed (such as kdebase-workspace-bin, for example). This group turned out to have everything I was missing. I have NO idea why these packages were not install during the upgrade, but this has been a weird one. (During the past few days, when checking if I had any updates, I was presented with what looked like have available dist-upgrades to KDE 4.5, which would have resulted in some strange installations AND removals had I applied it. I can only assume this was because the packages in the repositories were being updated over a few days and thus the lists had some old and new mixes that didn't jive quite perfectly until all were updated.)

Also, during the install I failed to update the /etc/kde4/kdm/kdmrc file to the newest version (my fingers slipped on the keyboard, if you can believe it). I don't think this was the cause of my problems, but I did manually upgrade that just to make sure.

Noteably ktorrent is not available in the Kubuntu PPAs because of a version dependency. Strange. Hope they fix that soon.

KDE 4.3 Fails to Load after System Update (Solution)

After installing my system updates yesterday, KDE 4.3 failed to load upon reboot this morning. It boots until it reaches the KDE login screen (with KDM) but it will let me log in from there at all.

The last updates installed were:

• Package: xserver-common, version 2:1.6.4-2ubuntu4.1
• Package: xserver-xorg-core, version 2:1.6.4-2ubuntu4.1

Though I suspect that the recent updates to gcc/g++ and libc/libstdc++ may have also affected this. I can't be sure.

Either way, I don't know exactly what the problem was, but here is the solution I found. My '.Xauthority' file in my home directory was the problem. I don't know what was wrong with it, but after I cleared that file of all contents, KDM let me log in normally. I hope this fix works for anyone else.