Create the user profile which contains the following lines:

# /etc/dconf/profile/user

user-db:user system-db:local

local is the name of a dconf database.

Create the directory /etc/dconf/db/local.d/ if it does not already exist.

Create the gdm profile which contains the following lines:

# /etc/dconf/profile/gdm

user-db:user system-db:gdm file-db:/usr/share/gdm/greeter-dconf-defaults

gdm is the name of a dconf database.

Update the system databases:

    # dconf update

Users must log out and back in again before the system-wide settings take effect.