Ubuntu 18.04 – Login Loop Even with Correct Password

I installed Ubuntu 18.04 yesterday, done some app installation and configurations and went to sleep. This morning, the login simply didn't work: the system is unable to log into my session, even with the correct password. Every time I try it, it flashes the screen into black and purple, the mouse pointer is available, but it flashes back to the login screen again: no error message prompts and I spent quite some time amusing myself trying to win it by attrition =). I also tried switch over to Wayland, and the same result: screen flashes to black, couple of seconds later, I'm back at the login stage.

There is nothing wrong with my password, since I can log into my user account on the Terminal (CTRL+ALT+F1). Once there, I did a sudo apt update/upgrade in the hopes it'd fix something, but my system was up to date and it didn't solve anything after I rebooted.

I've seen a lot of similar reports on the internet and the only solution that it seemed worthwhile to my noobish eyes was removing/deleting the .Xauthority file. But when I tried it, the return I got was that there was no such file on my Home directory. The other solutions applied to people upgrading their systems – mine was a fresh install – or with pretty specific hardware and conditions that don't apply to me.

So, what should I do to fix this?