On Sat July 14 2018 14:38:56 Stefan Krusche wrote:
(Manually) changed /etc/X11/default-display-manager back to tdm-trinity
This broke your installation and invalidated subsequent tests as /etc/X11/default-display-manager no longer matches the value in /var/cache/debconf/config.dat
dpkg-reconfigure is the way to go.
--Mike