We stopped supporting Xenial in April. At this point, the right choice would be to reach out to the Ubuntu Community.
That said, a tip: it’s using lightdm 1.18.1 as a display manager. According to the default config file at that time, as well as the wiki page, it seems it’s pretty easy.
On the other hand, there’s at least one known bug about autologin not working in Xenial. I couldn’t find any more detail on whether or not that issue has been confirmed or if there’s a resolution.
There’s also a possibility that using the
users-admin tool (that’s the “Users & Groups” thing in the menu) might have some bug in it, too. It may be presumptuous that it works natively with lightdm.
I don’t really have any Xenial virtual machines to test any of this, unfortunately.
What I can tell you is that in Bionic, when I set the “do not ask for password” setting, it doesn’t mean that it logs in automatically. It just means it doesn’t ask for the password. You still have to hit login.
Noumeno’s solution is correct there, though it should include
[Seat:*] and not
[SeatDefaults], so don’t change that.
My experience: lightdm is finnicky and generally poorly documented. sddm is way easier to work with. Just have to make my plug for the LXQt-equipped Lubuntu