After I'd upgraded my PCLinuxOS KDE 4.6.5 MiniMe 2012.02, to 'KDE 4.8.3' there were a couple of oddities, but nothing that couldn't be fixed.
However, since the upgrade when I booted I got an error message: "Can't find Blue Dobie", I'd hit Enter, Esc, whatever and continue to a lot of verbose outpourings. When that ceased I was offered a user@localhost command prompt.
This is the wierdest part.
I'd type login, then typed in my User; then PassWord, and out of sheer desperation typed (many things) "kde 4.8.3" which then logged me in.
Logging out I received even more Verbose chatter, things were 'committing suicide' which was funny the first time, but... when it settled, hitting Ctrl+Alt+Del restarted the Computer; which when it had settled again, I typed 'poweroff'. Which it did.
Earlier today I felt I should do something about this situation. Thoroughly unacceptable of course.
As I used the Blue Dobie Plymouth Theme, and had made a Live Usb before taking any steps to upgrade to 4.8.3, I thought if the Boot Error was 'can't find Blue Dobie' the fix may be a simple one.
Booted off the Live USB, found "usr/share/apps/kdm/themes/ Blue Dobie". I copied the directory to the same location on the Installed upgraded System whilst using the Live USB, and I can now login, and out, with a proper Graphical Theme. Who would've guessed.
Definitely an intuitive move but so glad to be without all the crazy stuff going on to Login, and Boot.
Posted as may be of help to someone, or some may find this entertaining.
Personally I'm greatly relieved, my KDE 4.8.3 upgrade is complete with all of the System working as it should. Phew !