How do I set the default desktop environment on 18.04 (Bionic)?

Question

I've installed Gnome Flashback and can select it on the log in screen:

Unfortunately, every time I restart I'm automatically logged into the original "Ubuntu" (Gnome 3) environment again. The solutions in these related questions don't work anymore:

how to set default session in Ubuntu 14.04 LTS?

How do I change the default session for when using auto-logins?

Specifically, setting user-session to gnome-flashback-metacity in /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf has no effect.

How do I fix this?

Solution 1

Found a workaround. Install LightDM (which IMHO looks much better than the default GDM):

sudo apt-get install lightdm

Then disable and re-enable autologin (if needed). This creates a working configuration that remembers your selected desktop environment.

Solution 2

$ sudo update-alternatives --config x-session-manager

(you can also add other DM via

sudo update-alternatives --install /usr/bin/x-session-manager x-session-manager /usr/bin/gnome-session-classic 60 

[assuming the new session manager is /usr/bin/gnome-session-classic :-]

Solution 3

You can change the default Desktop environment file in user Account file.

cd /var/lib/AccountsService/users

Select the specific user file

Here change the "xsession" value to "GNOME Flahsback (Metacity)"

Solution 4

You could reconfigure your default display manager using these steps in the terminal. I am assuming that your default is gdm3 and you want to move to lightdm

$ sudo dpkg-reconfigure gdm3
<OK>
lightdm

Solution 5

Run sudo dpkg-reconfigure gdm and select the default display manager in the dialog that pops up. You can replace “gdm” with any of the display managers that are currently installed on your system. If this fails, you can edit the /etc/X11/default-display/manager file with root privileges https://www.makeuseof.com/tag/choose-switch-linux-display-managers/

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Comments

[Daniel Böhmer]

I’ve tried this but dpkg-reconfigure doesn’t offer any choices and immediately ends with exit code 0.

[Will Matheson]

I needed unity, and was able to just specify unity (after installing it for 18.04), corresponding with the .desktop file in /usr/share/xsessions/ help.gnome.org/admin/system-admin-guide/stable/…