Having installed, updated and setup autologin in Zen works fine - then suddenly autologin fails.
Looking for the culprit, it appear that something is blindly writing:
in the first line of /etc/X11/gdm/custom.conf and not in any of the sections...
This stanza is ment to be written in the security section in this file.
Then autologin fails.
Editing this file manually until the culprit is found and amended.....