Debian Buster, KDE 3.5.10. aptitude
As more and more software-updates clash with their dependencies against
what KDE needs or provides, I wanted to install trinity, preliminary
stable, alongside KDE. KDE should stay operational till I had
transferred my settings and programs aso to trinity.
No go! 
Tdebase was fetched and seemingly installed, but when I restarted the
computer and wanted to start KDE, there was only a black screen with
the mouse-cursor and whatever I did with keyboard or mouse, nothing
happened. Cold reboot to clear memory, same thing.
Okay, let's then have a look at trinity. A blue screen with the logo
appeared and after a few seconds something like "no ..... available
check your installation"and I only could close that window via a warm
reboot. KDE gave me the black screen again and also TDE said
"check installation". 
Installed TDE again, same results as before. Half an afternoon had
passed with no desktop still available.
Glad, that I had backupped my system before the experiment and could
restore my working KDE. 
So there's also a clash between TDE and KDE, incredible!
Where should I look for the culprit for this disaster?
Kind regards.