RHEL 9 Boot Stuck at GDM? Here's How to Fix It (Step-by-Step)

Is your RHEL 9 system hanging at the "Starting GNOME Display Manager (GDM)" screen? Don't panic! This guide provides a clear, step-by-step approach to troubleshoot and resolve a system stuck at GDM. You'll be able to get back to your graphical environment in no time.

What is GNOME Display Manager (GDM) and Why Does it Matter?

The GNOME Display Manager (GDM) is the graphical login interface for Linux systems using the popular GNOME desktop. Think of it as the gatekeeper to your desktop, responsible for:

User-friendly login: Providing a visual interface for entering your username and password.
Session management: Starting and managing your GNOME desktop session.
Display server support: Working with both X11 (older) and Wayland (newer) display servers.

When GDM fails to start properly, you're locked out of your graphical environment.

Why Does GDM Get Stuck? Common Causes of "Starting GNOME Display Manager" Hangs

Several factors can lead to a frozen GDM screen. Here are the most frequent culprits:

Incomplete updates: A partially completed system update can leave your system in an inconsistent state.
Package conflicts: Conflicting software packages can interfere with GDM's operation.
Graphics driver problems: Outdated, corrupted, or incompatible graphics drivers are prime suspects.
Misconfigured system services: Improperly configured system services can prevent GDM from starting.

Troubleshooting a RHEL 9 System Stuck at GNOME Display Manager (GDM): Step-by-Step

Here's a tested methodology to resolve your GDM issue. Follow these steps in order for the best results.

1. Access a TTY Console

The first step is to break out of the frozen graphical screen.

Press Ctrl + Alt + F2 (or F3/F4) to switch to a TTY console – a text-based terminal.
Log in using your username and password.

This gives you a command-line environment to work with.

2. Restart the GDM Service

A simple restart can often resolve minor glitches.

In the terminal, execute: sudo systemctl restart gdm

This command attempts to restart the GNOME Display Manager service. If it was just a temporary hiccup, this might be all you need.

3. Examine GDM Logs for Clues

If restarting didn't work, it's time to investigate the logs.

Run the following command: journalctl -xeu gdm

This displays the system logs specifically for the GDM service. Scour through the output, looking for any error messages or warnings that might provide insight into the problem. These messages often point towards specific configuration issues or failing components.

4. Reset GNOME Desktop Settings

Corrupted GNOME settings can sometimes interfere with GDM.

Execute the following command to reset GNOME settings to their defaults: dconf reset -f /org/gnome/
After resetting, restart GDM: sudo systemctl restart gdm

This resets your GNOME configuration for the user.

5. Boot into Multi-User Mode (Command Line Only) for Deeper Troubleshooting

If the problem persists, boot into multi-user mode, which disables the GUI.

Reboot your system. During boot, access the GRUB menu by pressing Esc or Shift.
Edit the boot entry. Add systemd.unit=multi-user.target to the end of the line starting with linux.
Press Ctrl + X to boot.

This will boot your system into a command-line environment, allowing you to perform more advanced troubleshooting without the interference of the graphical interface. From here, you can investigate drivers, check system files, and perform other diagnostic tasks.

"Unsupported Session Type" Error? Here's the Fix

Sometimes, you might encounter an "Unsupported Session Type" error.

Check the Session Type: Run echo $XDG_SESSION_TYPE. If the output is tty instead of x11 or wayland, your graphical session isn't active.
Start GNOME Manually: Try starting GNOME manually with the command startx.
Set the System to Boot into Graphical Mode by Default:
- Check the current default target: systemctl get-default
- If it shows multi-user.target, change it to graphical: sudo systemctl set-default graphical.target
- Reboot your system

Conclusion: Getting Your RHEL 9 GNOME Desktop Back on Track

Dealing with as RHEL 9 boot stuck at GDM can be frustrating, hopefully the above tips will help. Remember to examine system logs, verify configuration settings, and keep your graphics drivers updated. These preventative steps will help avoid future issues.