Editing /etc/gdm3/greeter.dconf-defaults, as Jeremy suggested, works for me too. However, also the instruction in system-admin-guide works fine for me, so making an Ubuntu specific variant of that page seems not to be motivated. Possibly there is room for improvements of the upstream page.
@Fábio: Before suggesting anything, it would be valuable to know why it failed for you. For instance, did you successfully create the dconf database? For me it looks like this: $ ls -l /etc/dconf/db/gdm -rw-r--r-- 1 root root 240 mar 29 23:45 /etc/dconf/db/gdm ** Changed in: gnome-user-docs (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-user-docs in Ubuntu. https://bugs.launchpad.net/bugs/1759043 Title: gdm3 disable-user-list does not work bionic Status in gnome-user-docs package in Ubuntu: Incomplete Bug description: This how-to does not work on artful and bionic: https://help.gnome.org/admin/system-admin-guide/stable/login-userlist-disable.html.en GDM will always show the users list - even those logged remotely. There were a similar key for lightdm/unity that did work good. Version in use: gdm3 3.27.92-0ubuntu1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-user-docs/+bug/1759043/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp