On Monday 25 November 2019 19:59:29 Dr. Nikolaus Klepp wrote:
> just as a workaround: in /etc/rc.local add this line:
> ( sleep 10s; killall tdm) &

I have 3 computers with Debian Buster.

On the computers 1 and 2, tdm is in /etc/init.d/
they boot fine with tdm-trinity.
(dpkg-reconfigure tdm-trinity).

On the computer 3, no tdm is in /etc/init.d/
# dpkg-reconfigure lightdm
lightdm is in /etc/init.d/
and it works fine again, the computer boot on tde desktop.

A conflict between tdm-trinity and lightdm ?

# ps aux| grep tdm :
root 801  0.0  0.1  47508  8764 ?  Ssl  20:31 0:00 /usr/sbin/lightdm
root  819 0.8  0.7 103588 63256 tty7 Ssl+ 20:31:09 /usr/lib/xorg/Xorg :0 -seat 
seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
root 837 0.0  0.0 30180  6988 ? Sl 20:31 0:00 lightdm --session-child 12 15

What means tty7 ? It should be tty1 ?