Authentication Required弹窗导致笔记本无法登录且无法输入密码的问题求助

Hey there, sorry to hear you're stuck with this super frustrating login issue—nothing's worse than being locked out of your own laptop! Let me walk you through some practical fixes that have helped many users resolve this exact problem:

• First, escape to a TTY terminal (this lets you bypass the broken graphical login):
  Press Ctrl + Alt + F3 (or try F2-F6 if F3 doesn't work) to switch to a plain text login screen. Here, you should be able to type your username and password normally to log into a command-line session.

• Restart critical display and authentication services:
  A glitch in the display manager or polkit service is often the culprit. Once you're in the TTY:

  1. Try restarting your display manager (most systems use gdm, if you use lightdm replace it below):
     sudo systemctl restart gdm
  2. Press Ctrl + Alt + F1 to switch back to the graphical login screen and see if the issue is fixed.
  3. If that doesn't work, restart the polkit authentication service instead:
     sudo systemctl restart polkit
     Then switch back to the graphical interface again to test.

• Fix corrupted PAM configuration files:
  Sometimes messed-up PAM (Pluggable Authentication Modules) settings block password input. Here's how to reset them:

  1. First back up the current config file just in case:
     sudo cp /etc/pam.d/common-auth /etc/pam.d/common-auth.bak
  2. Reconfigure the PAM modules to restore default settings:
     sudo dpkg-reconfigure libpam-modules
  3. Follow the on-screen prompts (usually just press Enter to accept defaults) and then reboot your system.

• Check for filesystem errors:
  Corrupted system files from an unexpected shutdown can cause this issue. Run a filesystem check:

  1. First, identify your root partition using:
     df -h /
     Look for the entry under "Filesystem" (it'll look like /dev/sda1 or /dev/nvme0n1p2).
  2. Unmount the partition (if possible):
     sudo umount /dev/your_root_partition
  3. Run the filesystem check:
     sudo fsck /dev/your_root_partition
  4. When prompted, type y to fix any detected errors, then reboot.

If none of these steps work, you might need to boot from a live USB drive to access your system files and do deeper troubleshooting—but the above fixes should cover most common cases of this problem.

备注：内容来源于stack exchange，提问作者Harsh Sharma