# KDM doesn't start, & I can't re-assign GDM as KDM doesn't start

Dear Experts,

I seem to be in serious trouble and I do not want to reinstall Fedora OS.

I changed GDM to KDM by typing the command "system-switch-displaymanager kdm" in terminal (without the two symbols of "). At first I was told by the OS that KDM wasn't there. I installed KDM and typed that command again. This time I was told by the OS that GDM was changed to KDM. I restarted the OS eagerly. I didn't know this change of display manager was going to make me sad rather than happy.

What happens is that KDM doesn't start at all. I can't boot into Fedora with my username and password. The OS starts and the process stops at the point where the following line gets displayed on the screen (as the last line of a long sequence of lines):

started hostname service .... pt Dispatcher Service .... SEC.dmeventd or progress polling ....

I can only power off the CPU at this point. No command works at this point. No next line ever appears.

What should I do now? I understand that all I need to do is to run as superuser the command "system-switch-displaymanager gdm" but I can't do that unless I get to log in somewhere first with my username and password, and then start the terminal.

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Welcome to ask.fedora! I know that you feel that you have a chicken and egg problem here, but it's not hard to get back to where you were. Once you've booted as far as you can, use CTRL-ALT-F2 to change to a text-only console, which is the same (roughly) as a full-screen terminal. Then, log in and run system-switch-displaymanager kdm in there. Once you have a prompt again, log out and use CTRL-ALT-F1 to go back to your main console and kdm should come right up. If not, one last reboot should do the trick, unless there's something else preventing a normal full boot.

Good luck, Happy Holidays and please let us know how this works.

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Thanks sideburns. I ran the command system-switch-displaymanager gdm and this took me back to where I was. The command system-switch-displaymanager kdm doesn't work even if I run it in a text-only console that I can get to by using your magic code CTRL+ALT+F2. Reboots don't help either.

Does all this mean that there's something that isn't letting kdm start completely??

( 2017-01-02 17:06:10 -0500 )edit

It's possible that gdm is being started at boot. Run systemctl status gdm.service and see if it's active or not.

( 2017-01-02 18:18:35 -0500 )edit

I guess it's active:

" [gunjan@localhost ~]$systemctl status gdm.service ● gdm.service - GNOME Display Manager Loaded: loaded (/usr/lib/systemd/system/gdm.service; enabled; vendor preset: disabled) Active: active (running) since Mon 2017-01-09 04:11:34 IST; 14min ago Main PID: 672 (gdm) Tasks: 3 (limit: 4915) CGroup: /system.slice/gdm.service └─672 /usr/sbin/gdm Jan 09 04:11:33 localhost.localdomain systemd[1]: Starting GNOME Display Manager... Jan 09 04:11:34 localhost.localdomain systemd[1]: Started GNOME Display Manager. [gunjan@localhost ~]$

" What must I do??

( 2017-01-08 17:00:01 -0500 )edit

Thanks sideburns. The CTRL+ALT+F2 solution solved my problem. The command worked. It worked like a magic.

I didn't imagine that the solution could be so quick. I thought that a lot of operations would have to be executed.

I was so in trouble with no way to work on Fedora OS that I simply typed system-switch-displaymanager gdm after getting to a terminal by pressing the magic code CTRL+ALT+F2 and then I typed reboot. The Gnome Display Manager replaced KDM and started completely after the OS restarted. I've written this magic code and saved it in my notepad in which I take notes. :)

Now that I know how to get back to GDM if KDM doesn't start, I will see if your suggestions can help me in installing KDM in a manner that makes it start once I reboot after replacing GDM by KDM. I'll try this out and see whether I can start KDM or not. If KDM starts I'll tell you that your suggestions helped me in installing KDM. If KDM doesn't start then I'll get back to GDM and tell you that your suggestions didn't help. Maybe you or someone can then conclude that something else is preventing a normal full boot and then diagnose what the root cause is and then troubleshoot that cause. I'll get back to you soon. Kindly wait for some time.

Happy Holidays. And thank you.

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