I cannot login to my system, plz help!
1. Try logging in text mode
Switch to text mode (Ctrl+Alt+F5) and try to login, if you are able to do it then the problem is with your graphical login manager.
2. Remove configuration files
To determine whether configuration in your home directory is causing the issue, you can create a new user account for testing purposes:
sudo adduser test
sudo systemctl reboot
If you’re able to log in with the test user, the issue is somewhere in your regular user’s home folder. Log into the full-screen terminal with your regular user again, and move some of the common configuration files out of the way:
mv ~/.config ~/.config.old
mv ~/.local ~/.local.old
mv ~/.cache ~/.cache.old
mv ~/.bashrc ~/.bashrc.old
mv ~/.zshrc ~/.zshrc.old
# and possibly many more, depending on your setup
sudo reboot
After moving those files and rebooting, try logging in again.
🎉 SOLVED my problem 🎉
.bashrc was causing the problems. I put exec zsh in the beginning of this file. I do not exactly know why it caused this bug but will definitely research this one :-)
3. Reinstall login manager
You can reinstall GNOME Display Manager (which handles the login screen), along with the desktop environment. On Pop!_OS:
sudo apt install --reinstall gdm3 pop-desktop gnome-shell
sudo systemctl reboot
4. Reinstall drivers
The Nvidia or Radeon drivers can cause the bug, see this tutorial
References
Kudos to System76 team for once again solving my problem (previously I had one with bootloader).