I had the same issue: my user name does not appear when login after upgrade Ubuntu/ gdm3 from 20.04 to 22.04. It is in "not listed" user accounts. I click "not listed", can login.
Solved by changing my user account to regular and reinstalling gdm3
checked out solutions in but failed https://askubuntu.com/questions/1234452/ubuntu-20-04-user-not-listed-to-login
I found my user account was changed to SystemAccount=true in the file /var/lib/AccountsService/users/my_username.
Change to regular user account, which will be showed up when login.
- sudo su
- cd /var/lib/AccountsService/users
- vim my_username
change SystemAccount=true =>
SystemAccount=false
failed to show up when login.
However Display Manager switched to lightdm or sddm, my user appears when login https://techpiezo.com/linux/switch-display-manager-in-ubuntu-22-04/
reinstall gdm3, solved my problem.
- sudo apt purge gdm3
- sudo apt install gdm3
Solved.
gsettings get org.gnome.login-screen disable-user-list
?$ gsettings get org.gnome.login-screen disable-user-list
falsenano greeter.dconf-defaults
tell you? Is there something activated under# Login manager options
like# disable-user-list=true
?/etc/gdm3/greeter.dconf-defaults
. I don't see a non-commented-out line that starts withdisable-*
. Pasting content here. The one under/usr/share/gdm/greeter.dconf-defaults
seems to have the same content.