I've been trying to set this up, but I can't find a solution. It's neccessary, because the machine Ubuntu is on is a Macbook and needs to have access to the files of the Mac user. Is there any way to get this to work?
Lightdm has the config file
You will probably also want to change the defaults for adduser & useradd, to create new users with UID starting at 500.
Two files need change, as: