How to change display manager for Ubuntu, Kubuntu or Debian

In a Linux environment, the display manager, or login manager, is responsible for starting the graphical user interface (GUI) session after user login. Ubuntu uses GDM3 (GNOME Display Manager) by default, while Kubuntu uses SDDM (Simple Desktop Display Manager). Other options like LightDM, XDM, and LXDM are also available, each offering different features and performance characteristics. Changing the display manager allows users to customize their login experience and ensure compatibility with their chosen desktop environment.

Changing the display manager on Ubuntu is a straightforward process using package management tools like apt and dpkg-reconfigure. When a new display manager is installed, the system prompts the user to choose which manager to use. This process involves simple terminal commands, making it accessible even for users with basic command-line knowledge. This flexibility benefits users who need to switch between different desktop environments or optimize their system’s performance and interface.

On Debian-based systems, including Ubuntu, the dpkg-reconfigure command is essential for selecting and configuring the default display manager. This tool allows users to reconfigure packages and select their preferred display manager from installed options. The switch involves checking the current display manager status, selecting the new manager, and rebooting the system to apply the changes. This method ensures a smooth transition, enhancing the user experience by aligning the login interface with personal preferences or specific system requirements.

1. Launch terminal.
2. Check the current display manager using systemctl.
3. Install your desired display manager if it's not already installed.
4. Use dpkg-reconfigure to configure default desktop manager.

   $ sudo dpkg-reconfigure gdm3
   [sudo] password for user: 

   Replace gdm3 with the display manager you want to use. For example, sddm for Kubuntu.

   systemctl will gracefully exit if no other display manager is installed.

   

5. Use arrow key to select your preferred display manager, use <tab> key to navigate to the Ok button and press [ENTER].

   Use <tab> key to navigate to the Ok button and press [ENTER] if you're first presented with the following screen. You'll get this screen if you're using a low resolution monitor and/or not running terminal in full screen.

6. Reboot your system to start using the newly selected display manager.