Fix “Failed to start gdm.service – GNOME Display Manager” on Ubuntu (Lenovo, Dell, HP & Others)

Last Updated: November 2025
Works for Ubuntu 20.04 / 22.04 / 24.04, Pop!_OS, Debian, Mint, Zorin OS, etc.
Tested on: Lenovo ThinkPad, Dell Inspiron/Latitude, HP ProBook/Envy, ASUS & Acer systems

Ubuntu GDM fix, Failed to start gdm.service solution, Ubuntu black screen after login, GDM vs LightDM, Lenovo ThinkPad Ubuntu boot issue, Dell Ubuntu secure boot disable, HP Ubuntu AHCI mode, Ubuntu NVIDIA driver fix, Ubuntu GUI not starting, Ubuntu display manager problem,

Introduction

If your Ubuntu suddenly boots to a black screen or text-only console showing:

Failed to start gdm.service – GNOME Display Manager

Don’t worry—your system isn’t broken.
This error means your graphical login (GDM) failed to start—usually because of:

A blocked graphics driver (e.g., Secure Boot + NVIDIA)

Wrong BIOS storage mode (RAID/VMD instead of AHCI)

Corrupted GDM or GPU configuration

This guide explains how to fix it step-by-step on Lenovo, Dell, HP, and other laptops, even if you don’t have a USB flash drive.

Prerequisites

Before we begin, make sure you can:

Access a TTY terminal by pressing Ctrl + Alt + F3 or F4

Log in with your username and password

Have an internet connection (Wi-Fi or Ethernet). 

Step 1—Enter BIOS/UEFI Settings

Different brands have slightly different BIOS access keys:

Brand

BIOS Key

Boot Menu Key

Lenovo (ThinkPad / IdeaPad)

F1

F12

Dell (Inspiron / Latitude / XPS)

F2

F12

HP (Pavilion / ProBook / Envy)

Esc → F10

Esc → F9

ASUS / Acer / MSI

F2

F12 or Esc

Power on your laptop and press the key repeatedly during startup.

Step 2—Disable Secure Boot

Reason: Secure Boot blocks unsigned GPU drivers (especially NVIDIA), preventing GDM from starting.

BIOS Navigation:

Lenovo: Security → Secure Boot → Disable

Dell: Boot Configuration → Secure Boot → Disabled

HP: Security → Secure Boot Configuration → Secure Boot → Disable

Save and exit (usually F10) and reboot.

Then, verify inside Ubuntu CLI:

				
					sudo mokutil --sb-state
				
			

It should say:

Secure Boot disabled

Step 3—Change Storage Mode (RAID → AHCI / VMD → Disabled)

Reason: Ubuntu sometimes can’t boot properly or detect NVMe drives when Intel RST/VMD is enabled.

BIOS Path by Brand:

Brand

Menu Path

Change To

Lenovo

Config → Storage / VMD Controller → Disabled

AHCI mode

Dell

Storage → SATA Operation → AHCI

From “RAID On”

HP

Advanced → Storage Options → AHCI

Disable Intel RST if shown

If Windows was preinstalled with RAID/RST mode, switching may stop it from booting — backup first.

After saving BIOS changes, reboot back into Ubuntu CLI.

Step 4—Update & Repair Packages

In your Ubuntu terminal (Ctrl+Alt+F3):

				
					sudo apt update
sudo apt install --fix-broken -y
sudo dpkg --configure -a
sudo apt upgrade -y

				
			

This ensures all system components are synced before repairing GDM.

Step 5—Reinstall & Reconfigure GDM

				
					sudo rm -f /etc/gdm3/custom.conf
sudo apt install --reinstall gdm3 -y
sudo dpkg-reconfigure gdm3

				
			

When asked, choose gdm3 (not lightdm).
Then try restarting the display manager:

				
					sudo systemctl restart gdm

If it fails again:

sudo systemctl status gdm --no-pager
sudo journalctl -xeu gdm

				
			
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Step 6—If GDM Still Fails, Use LightDM

Switching to a lighter login manager often bypasses GDM/driver bugs:

				
					sudo apt install lightdm -y
sudo dpkg-reconfigure lightdm
sudo reboot

				
			

Choose LightDM when prompted.
After reboot, your graphical login screen should return.

Step 7—Fix GPU Drivers (Intel / NVIDIA / AMD)

Check your GPU:

				
					lspci | grep -E "VGA|3D"
				
			

Intel

Usually works out of the box. Just update:

				
					sudo apt install --reinstall xserver-xorg-video-intel -y
				
			

NVIDIA

				
					sudo ubuntu-drivers autoinstall
sudo reboot

				
			

If GDM still fails, disable Secure Boot again in BIOS and repeat.

AMD

				
					sudo apt install --reinstall xserver-xorg-video-amdgpu -y
				
			

Step 8—Rebuild Initramfs & GRUB (after BIOS changes)

If you changed RAID → AHCI / VMD → Disabled:

				
					sudo update-initramfs -u
sudo update-grub
sudo reboot

				
			

Step 9—Use GRUB Recovery (if the GUI won’t start at all)

Reboot → hold Shift or Esc → open GRUB menu.

Select Advanced options for Ubuntu → (recovery mode)

Choose root to open a repair shell.

Run the same repair commands from above.

 

Step 10—Verify & Troubleshoot

Check what’s working and what’s not:

				
					sudo systemctl status gdm
sudo mokutil --sb-state
lspci | grep -E "VGA|3D"
df -h
lsblk -f

				
			

Step 11—Summary

Problem

Fix

GDM fails to start

Reinstall gdm3 or switch to lightdm

Black screen after boot

Disable Secure Boot

Disk not visible

Switch BIOS from RAID/VMD → AHCI

NVIDIA drivers not loading

Run ubuntu-drivers autoinstall

GUI still missing

Rebuild initramfs + grub


Final Thoughts

Most “Failed to start gdm.service” issues are caused by BIOS security or storage modes blocking Linux from initializing GPU drivers.
For Lenovo, Dell, and HP laptops, disabling Secure Boot, changing RAID to AHCI, and reinstalling gdm3 or lightdm usually fixes the issue completely — no USB or OS reinstall needed. 

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