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marinecomm
August 31st, 2013, 01:50 PM
Last night I edited the default-display-manager file and changed my default display manager from lightdm to lightdm-gtk-greeter. Then I edited the lightdm-gtk-greeter config file and changed the wallpaper. Now, when I reboot the computer I get a whole string of messages where the computer is booting up but it freezes and won't boot into the system. It just hangs there. How do I get back into my system? I'm running Xubuntu 12.04 64-bit.

steeldriver
August 31st, 2013, 02:13 PM
Can you get to a virtual terminal (Ctrl-Alt-F1 etc.)? if so, you should be able to revert the changes from there

I've never messed much with greeters but shouldn't the lightdm-gtk-greeter line have gone in /etc/lightdm/lightdm.conf ('greeter-session=lightdm-gtk-greeter'), rather than in /etc/X11/default-display-manager? That should stay as /usr/sbin/lightdm surely?

marinecomm
August 31st, 2013, 02:20 PM
I don't know how to get to a terminal. Like I said, the system goes through a string of commands while loading up then freezes/hangs up. It doesn't stop and go to a command prompt. i'm not sure how to stop the system from loading and get to where I can enter commands.

steeldriver
August 31st, 2013, 02:24 PM
It's in my previous post - key combination Ctrl-Alt-F1 (or Ctrl-Alt-F2, ... etc. - Ctrl-Alt-F7 usually returns you to the screen it's trying to start the GUI on)

If that doesn't work then you will need to boot into 'recovery mode' from the grub menu

GwL3eNC
August 31st, 2013, 02:26 PM
Hi,

let the system load. If you think the ponit of hang is arrived press, like steeldriver told CTRL+ALT+F1, we must
first know if you can reach a terminal with it.

marinecomm
August 31st, 2013, 02:27 PM
If I can get to a virtual terminal what commands do I issue?

marinecomm
August 31st, 2013, 02:35 PM
Ok, I'll try and see if I can get a virtual terminal and then let you know.

steeldriver
August 31st, 2013, 02:39 PM
I would suggest running a package reconfiguration


sudo dpkg-reconfigure lightdm

which I *think* will re-insert lightdm as the default display manager automatically, and possibly restore other default lightdm configs. Then check if the default-display-manager looks OK


cat /etc/X11/default-display-manager

If it didn't get reset to /usr/sbin/lightdm for some reason, then you can do that manually either by editing using nano


sudo nano /etc/X11/default-display-manager

(once you've made your changes, press Ctrl-o to save and Ctrl-x to exit); or (maybe easier) just run the following one-liner


echo "/usr/sbin/lightdm" | sudo tee /etc/X11/default-display-manager

marinecomm
August 31st, 2013, 02:45 PM
When the grub screen came up I decided to try to see if I could get in under recovery mode. I choose to boot in safe graphics mode. However, instead of booting in recovery mode it looped back and took me back to the recovery mode options screen. I opted for a normal boot. This time, when the system hung up I hit Ctrl-Alt-F1 and I was able to get a virtual terminal and sign in. I'll try those commands and see what it comes up with.

steeldriver
August 31st, 2013, 02:53 PM
Thinking about it some more, it may be enough just to start lightdm manually from the Ctrl-Alt-F1 screen


sudo service lightdm start

(it shouldn't matter in this context that it's not the default DM) - if that works, and gets you back to your regular session, then you can revert your changes in whatever favorite GUI editor you used before, if you prefer.

marinecomm
August 31st, 2013, 02:57 PM
Issued the command:

sudo dpkg-reconfigure lightdm

It changed my display manager back to lightdm and allowed me to log in. I'm back in business now. Thank you for all the help.

steeldriver
August 31st, 2013, 03:09 PM
Great. Happy to help.