How to repair login screen without reinstalling gdm

ubuntu-9.10 gdm

7,581

I was able to recreate your issue pretty easily; I enabled assistive technologies from the System > Preferences > Assistive Technologies dialog, then logged out, opened the Assistive dialog, checked the checkbox for the high-contrast view, unchecked the checkbox, and closed the dialog. That changed the user list coloration, and didn't restore the default theme.

This appears to be a known bug. They call it ACODBIT -- the Accessibility Checkbox Of Death By Inappropriate Theme.

What's happening is that checking the accessibility option changes a GDM configuration file when checked, and when unchecked the file isn't properly restored.

The file is /var/lib/gdm/.gconf.defaults/%gconf-tree.xml; all you need to do to fix the problem state is restore the original file. There are several ways to do this; which ones are easier than reinstalling ... is debatable. An incomplete list:

Copy the file from another system that doesn't exhibit the problem. This could be another computer running Ubuntu 9.10, or a 9.10 LiveCD.
Mount a LiveCD's casper/filesystem.squashfs file and access the file from there:
1. insert your LiveCD and allow Gnome to automount it;
2. in a terminal window, run this to mount the LiveCD's filesystem
  (replace /media/cdrom0 with the location your LiveCD was mounted to):
```
sudo mount /media/cdrom0/casper/filesystem.squashfs /mnt -o loop
```
3. copy the file from LiveCD filesystem:
```
sudo cp /mnt/var/lib/gdm/.gconf.defaults/%gconf-tree.xml /var/lib/gdm/.gconf.defaults/
```
Restore it from a backup, if you have one.
Reinstall the gdm package. For beginners, this really is the easiest option. If the package is still available in your system's package cache (/var/cache/apt/archives), reinstalling will not re-download the package. You can use one of these to reinstall:
- Synaptic Package Manager, on the System > Administration menu; or
- Aptitude on the commandline, with the command
```
sudo aptitude reinstall gdm
```

7,581

Akoi Meexx

dev_languages = {'general':'python', 'general':'vb', 'web':'css', 'web':'js', 'web':'php', 'web':'xhtml', 'database':'mysql',} design_skills = {'graphics':'The GIMP', 'graphics':'Inkscape', 'graphics':'MS Paint', 'graphics':'Photoshop',} useful_skills = {'dev':'Regex Magic', 'design':'User Experience', 'personal':'Patience',} personal_info = {'goal':'world domination', 'alignment':'neutral evil', 'answer':'42', 'quote':'...',} links = {'REST':'http://rest.elkstein.org/', 'Search':'http://www.google.com/',}

Updated on September 17, 2022

Comments

Akoi Meexx over 1 year

I recently ran into an issue with my login screen switching to a default hi-contrast window management schema in Ubuntu, as opposed to the default dark colors. The problem (and a working, but not-as-versatile solution) is documented at http://ubuntuforums.org/showthread.php?t=1324055.

How do I reconfigure my system to use the default settings when at the login screen, without reinstalling gdm?
quack quixote about 14 years

my question is, now that i've enabled the "Assistive Technologies" in order to test this bug, how the hell do i make it go away?? dammit, ubuntu... this is why i'm never again installing you on my own bare-metal machines.
quack quixote about 14 years

ok, apparently you disable "Assistive Technologies" by going into System > Preferences > Keyboard, select the "Accessibility" tab, and uncheck "Accessibility features can be toggled with keyboard shortcuts" ... *grumbles*