I believe this is fixed by the the recent SRU (1.18.2-0ubuntu2 in xenial-proposed). Can you confirm if that is the case?
** Changed in: lightdm (Ubuntu) Status: New => Triaged -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1605991 Title: Multiseat login stopped working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1605991/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs