How to completely reinstall lightdm

[mattdiamond17]

Hello. Yesterday i tried to install a theme for lightdm. I "installed" and then when rebooting, for some reasons, it was stuck on the splash screen of elementary os. So i've opened elementary in recovery mode and then i managed to install gdm and i've booted into my system. I searched all the day for a way to install lightdm, but every solution that i founded haven't worked. Currently i'm with gdm but i don't like how it looks(don't ask) and i want to replace with lightdm. How can i do that. Every time when i try to install lightdm again from the terminal, the installation freezes at 0% and stays like that for hours. Can someone please help me? I am using elementary os Loki 0.4.1 64 bit

[deadflowr]

Thread moved to Ubuntu/Debian BASED

[tinylagarto]

Is lightdm installed right now?

apt policy lightdm

from the terminal will tell us.

How did you install lightdm?

To install:

sudo apt install lightdm

If you want to change the login manager, proceed like this:

sudo dpkg-reconfigure lightdm

to change the defaults.

Normally when you install another login manager you will be asked which one to use.

I guess that should work in the same manner on ElementaryOS.

I posted some terminal commands because they work on any system in the same way. You could of course install lightdm from your app or software center.

[mattdiamond17]

So, this is what i get after running the first command:

lightdm:
Installed: 1.18.3-0ubuntu1.1
Candidate: 1.18.3-0ubuntu1.1
Version table:
*** 1.18.3-0ubuntu1.1 100
100 /var/lib/dpkg/status
1.18.1-0ubuntu1 500
500 http://archive.ubuntu.com/ubuntu xenial/main amd64 Packages


And if I remember good, i've installed with sudo apt-get install lightdm, after running sudo apt-get purge lightdm. Is this good?
Oh and if it helps, with lightdm selected it says while booting: Failed to start Light Desktop Manager. I think that means that lightdm can't start.

[again?]

What is your output for...

lightdm --show-config

[mattdiamond17]

It says:

Failed to load configuration from /etc/lightdm/lightdm.conf: Key file does not start with a group

sorry, but i don't know how to put my commands like you have done

[again?]

Output for...

cat  /etc/lightdm/lightdm.conf

To put in code blocks when replying see HERE.
Basically reply in advanced mode, paste in your output, highlight the text with left mouse and then hit the "#" icon.

[mattdiamond17]

Output:

greeter-session=lightdm-webkit-greeter

Thanks for the link!

[again?]

It says:

Failed to load configuration from /etc/lightdm/lightdm.conf: Key file does not start with a group

sorry, but i don't know how to put my commands like you have done

Output:

greeter-session=lightdm-webkit-greeter

Thanks for the link!

As shown in error output, "/etc/lightdm/lightdm.conf" does not have a group heading and should look like this...

[Seat:*]
greeter-session=lightdm-webkit-greeter

This command will correct the file...

echo -e "[Seat:*]\ngreeter-session=lightdm-webkit-greeter" | sudo tee /etc/lightdm/lightdm.conf

Then try again...

lightdm --show-config

[mattdiamond17]

OK. Thanks a lot for the reply.

So here is my output:

   [Seat:*]
B  greeter-session=lightdm-webkit-greeter


Sources:
A  /usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf
B  /etc/lightdm/lightdm.conf

It is good?