Login loop after installing 20.04

I fixed the bug with my Ubuntu 20.04 and Nvidia RTX 2080 as follows:

1. Do not check the box the automatic loggon during installation.
2. First start Ubuntu with your password
3. Move on Parameter, users, and check the box for the automatic login (after unlocking).
4. Reboot Ubuntu.
5. In GRUB, select advanced options for Ubuntu, then recovery mode.
6. Select the 'root' mode.
7. Write: sudo nano /etc/default/grub
8. Replace GRUB_CMDLINE_LINUX_DEFAUT="quiet splash" with GRUB_CMDLINE_LINUX_DEFAUT="quiet" (i.e. delete splash).
9. CTRL+X then Y then ENTER
10. Write, sudo update-grub
11. Write either reboot or exit then resume

It works for me for starting Ubuntu 20.04 without my password.

Good luck, my opinion is this 20.04 is not suitable for a novice, few months should be waited before installation (especially if you use a nas at home, there also is a serious bug with samba client used by nautilus).

At the boot screen, go to "Advanced options for Ubuntu". Then select the option that has "recovery" in it. At the recovery menu, the first option is "resume - Resume normal boot". Press enter in this option and enter again in the next screen. Now enter your password and the desktop will show up. Press "windows" button and type "login". Press enter and then click on "unlock" at the top. Type your password and deactivate "automatic login". There is a bug with nvidia drivers and automatic login. What I described worked for me, without having to install or remove anything. the only annoyance is having to typr the password at login.

If some of the answer above doesn't work and you previously installed chrome remote desktop,switch to TTY pressing ctrl + alt + f3 and executing sudo apt-get purge chrome-remote-desktop for uninstalling, hope this solve the problem