If you are like me frustrated and pulling hairs for fixing login loop in Ubuntu GNOME DE, and you tried everything that's written their on internet like purging nvidia, removing .Xauthority file, chmod/chown /tmp folder and so on... then let me tell you my friends what really works for me :) First of all there is something kicking out us from spawning DE and in order to see that we must see the logs and understand if anything not happening right, for that just scroll the logs ctrl + alt + f1 $ journalctl -xe | less and here my friends after closer look I found that gnome-shell extension are messing up with my DE boot, and just simply removing extension dir, voila I can login 💃 $ rm -rf ~/.local/share/gnome-shell/extensions $ reboot I hope this solves your issue too..
Some#random('thoughts'); // technical, non technical