DEV Community

Cover image for fixing Ubuntu login issues, including login loops, .Xauthority problems, and home directory permission issues.
Rajib Ahmed
Rajib Ahmed

Posted on

fixing Ubuntu login issues, including login loops, .Xauthority problems, and home directory permission issues.

#loginloops #xauthorityproblems #ubuntu #xauthority

fixing Ubuntu login issues, including login loops, .Xauthority problems, and home directory permission issues.

A comprehensive solution for fixing common Ubuntu login issues, including login loops, .Xauthority problems, and home directory permission issues.

🚨 Common Ubuntu Login Issues

This script addresses the following common login problems:

  1. Login Loop - You enter your password correctly, but the screen goes black and returns to the login screen
  2. .Xauthority Issues - Corrupted X authority files preventing GUI login
  3. Home Directory Permission Problems - Incorrect ownership or permissions on home directory
  4. Temporary Profile - System creating temporary profiles due to file access issues
  5. Display Manager Problems - Issues with GDM3, LightDM, or SDDM configuration

📋 Prerequisites

  • Ubuntu/Debian-based Linux distribution
  • Root/sudo access
  • Access to TTY console (Ctrl+Alt+F3)

🚀 Quick Start

Direct Run From GitHub Repo

Run the script directly without downloading a local file:

curl -fsSL https://raw.githubusercontent.com/rajibdpi/ubuntu-login/main/fix.sh | sudo bash
Enter fullscreen mode Exit fullscreen mode

From the Login Screen

If you're stuck at the login screen:

  1. Press Ctrl+Alt+F3 to access a text console
  2. Login with your username and password
  3. Run the fix script directly from GitHub: 
# Run the script (will auto-detect your username)
curl -fsSL https://raw.githubusercontent.com/rajibdpi/ubuntu-login/main/fix.sh | sudo bash
Enter fullscreen mode Exit fullscreen mode

Manual Usage

If auto-detection picks the wrong user, set the target explicitly:

curl -fsSL https://raw.githubusercontent.com/rajibdpi/ubuntu-login/main/fix.sh | sudo bash -s -- --user username
Enter fullscreen mode Exit fullscreen mode

Replace username with the actual username that has login issues.

Optional: Reset GNOME User Config

If login issues are caused by broken GNOME user settings/extensions, run with:

curl -fsSL https://raw.githubusercontent.com/rajibdpi/ubuntu-login/main/fix.sh | sudo bash -s -- --reset-gnome
Enter fullscreen mode Exit fullscreen mode

🔧 What the Script Does

The script performs the following fixes:

1. Auto-Detects Target User

  • Uses SUDO_USER first
  • Falls back to logname
  • Final fallback is first regular local user (UID >= 1000)

2. Fixes .Xauthority and .ICEauthority

  • Backs up existing files with timestamp suffix
  • Removes broken authority files that can cause login loops

3. Repairs Ownership and PATH in User Shell Files

  • Runs ownership repair on the user home directory
  • Backs up .profile, .bashrc, .bash_profile, .zprofile, .zshrc
  • Appends a safe PATH export to .profile and .bashrc if missing

4. Repairs Core Desktop/Login Packages

  • Runs apt-get update
  • Runs apt-get -f install -y and dpkg --configure -a
  • Reinstalls gdm3, gnome-shell, ubuntu-session, and xorg
  • Enables gdm3

5. Optional GNOME Profile Reset

  • With --reset-gnome, backs up and resets:
    • .config
    • .local/share
    • .cache

6. Rewrites Global PATH in /etc/environment

  • Backs up existing /etc/environment
  • Rewrites it to:
    • PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"

⚠️ Safety Features

  • Creates backups of all files before modification
  • Validates target user and home directory before making changes
  • Requires root privileges for safety
  • Uses strict Bash mode (set -euo pipefail)

🔍 Troubleshooting

If the script doesn't resolve your issue, try these additional steps:

1. Check System Logs 

journalctl -xe
Enter fullscreen mode Exit fullscreen mode

2. Reconfigure Display Manager 

# For GDM3
sudo dpkg-reconfigure gdm3

# For LightDM
sudo dpkg-reconfigure lightdm
Enter fullscreen mode Exit fullscreen mode

3. Check for Disk Space Issues 

df -h
Enter fullscreen mode Exit fullscreen mode

If your disk is full, clean up space:

# Clean apt cache
sudo apt-get clean

# Remove old kernels
sudo apt-get autoremove
Enter fullscreen mode Exit fullscreen mode

4. Verify Home Directory Permissions 

ls -la /home/username
Enter fullscreen mode Exit fullscreen mode

The home directory should be owned by the user with 755 permissions.

5. Check Authentication Logs 

sudo tail -f /var/log/auth.log
Enter fullscreen mode Exit fullscreen mode

6. Try Creating a New User

As a test, create a new user to see if the issue is system-wide:

sudo adduser testuser
Enter fullscreen mode Exit fullscreen mode

🐛 Known Limitations

  • The script must be run from a TTY console or SSH session, not from the GUI
  • Requires sudo/root access
  • Reinstalling packages requires network access to apt repositories
  • The script rewrites /etc/environment PATH to a known-safe value

💡 Prevention Tips

To avoid login issues in the future:

  1. Regular Backups - Keep backups of your home directory
  2. Monitor Disk Space - Keep at least 10% free space
  3. Careful with Permissions - Avoid using sudo with GUI applications
  4. Update Regularly - Keep your system updated
  5. Graceful Shutdowns - Always shutdown properly to avoid file corruption

🤝 Contributing

Contributions are welcome! Please feel free to submit issues or pull requests.

📄 License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.

🙏 Acknowledgments

This script was created to help users resolve common Ubuntu login issues based on community solutions and best practices.

⚡ Emergency Recovery

If you cannot access TTY console:

  1. Boot from Ubuntu Live USB
  2. Mount your main partition
  3. Chroot into your system
  4. Run the fix script
  5. Reboot

Example:

sudo mount /dev/sdaX /mnt
sudo mount --bind /dev /mnt/dev
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys /mnt/sys
sudo chroot /mnt
curl -fsSL https://raw.githubusercontent.com/rajibdpi/ubuntu-login/main/fix.sh | bash
exit
sudo reboot
Enter fullscreen mode Exit fullscreen mode

Replace /dev/sdaX with your actual root partition.

Top comments (0)