I just did a fresh installation of Ubuntu 14.04. To not break anything, I created the default user during install, but I neither need nor want it. I added my usual users (UIDs > 10000), which work great.
Now I want to remove the user that I created during the installation from the greeter.
Using gdm I would usually put
[greeter]
Exclude = dummy
into /etc/gdm/custom.conf as described on the gnome homepage. When using lightdm, I would use its minimum-uid setting in /etc/lightdm/users.conf like this:
[UserAccounts]
minimum-uid=1001 #1100 10000 11000 <-- other attempts
as suggested here and reading the comments in users.conf this is also very intuitive.
However, it would seem gdm and lightdm couldn't care less about my configuration settings. The users set up on this system will change so I would rather use the facilities to exclude certain users, rather than keeping the display manager configurations up to date.
How can I make Ubuntu care for my display manager settings? Do I need to enable this somewhere?
I even went tried the Windows way of rebooting a few times ...
As a next step I will delete this default user, but I don't know if this has some side effects on the Ubuntu installation.