Ubuntu – How to configure lightdm to allow manual logins in Ubuntu 14.04

NOTE: I also posted this answer here

I found a very simple workaround that works perfectly for me running 13.04. on a laptop with a 24" external screen that is not permanently connected.

I'll just copy from here

1. log in
2. use xrandr or the Displays control utility to configure your monitors how you'd like them to be configured in the login screen
3. sudo cp ~/.config/monitors.xml /var/lib/lightdm/.config/

Since I already had my monitors configured properly I just had to do step 3.

Overview

The badges for the Lightdm are stored in /usr/share/unity-greeter.

You can possibly add a new badge to the directory mentioned above. I guess you would want to name it as custom_awesome_badge.png or whatever is the name of the session in /usr/share/xsessions/. All the badges are of 22 x 22 pixels.

From the lightdm maintainer on the ubuntu-devel list:

1. Take /usr/share/unity-greeter/unknown_badge.png and use it as a template (just a 22x22 white circle).
2. Add your logo as a transparent cutout of the white circle (see other badges in that directory for examples)
3. Ship your logo as /usr/share/unity-greeter/custom_SESSIONNAME_badge.png, where SESSIONNAME is your X session name (e.g. 'xfce' for XFCE).

Unity Greeter will automatically look there, falling back to the generic white circle icon if not found.

Set of ready-made custom badges

You can download a large set of additional badges here. To install them just copy the folder content to /usr/share/unity-greeter.