Login Loop Fix for Ubuntu 20.04 with Nvidia Drivers
 

I've been dealing with a login loop issue this whole weekend and I have no clue what caused it! I was originally using Ubuntu 18.04 and suddenly I got stuck in a login loop after installing the proper nvidia drivers for my laptop.

For reference it's a Thinkpad P1 with a Nvidia Quadro 2000.

Anyways, I gave up but learned a bit about grub settings and disabling nouveau drivers and such, but nothing worked for me. So I gave up and decided to install Ubuntu 20.04 since it was just released.

It was great because it came with the latest Nvidia 440 driver installed and no issues!Thanks to this saint,

https://displaylink.org/forum/showpo...4&postcount=13

I figured out how to install display link drivers on 20.04. Everything went great yesterday with the new drivers and then I open my laptop today after work and I got a login loop! I tried a few things I didn't try with 18.04:

Tried startx and looked at the logs. Looks like it was having an issue with nvidia driver again...

But then something hit me, what If I make a new user. I make a new user and voila! I can login and graphics work! What is going on?!

Logically then this must not be a setting in the OS, but some configuration in the user settings, therefore it must be something within the /home/<user> directory.

I start commenting everything out in my bashrc and config files and then I notice, I have a .cache directory. I delete that sucker and graphics work again!

I'm thinking that startx or display link potentially look at information in the cache and maybe because I put my laptop to sleep mode it corrupted the cache and wouldn't start again.

So the takeaway from here is this:

If you get stuck in a login loop, try making a new user
Try to login and if graphics work, then you have an issue with your /home/user/.cache directory.

In the login screen press CTRL + ALT + F3, log in and
This might or might not fix your issue.