Just installed Slack 12 yesterday, was messing around with getting ALSA configured and needed something to test sound with, so I popped in a DVD that containing some AVI versions of a popular sci-fi TV show. XFCE detected the DVD in the drive and put a "New Disc" icon on my desktop. I double-clicked it and got an error message that "A security policy in place prevents this sender from sending this message to the recipient, see message bus configuration file (rejected message had interface "org.freedesktop.Hal.Device.Volume"..." and I'm not sure of the rest
Since I'm not logged into X as root, I figured this to be a permission problem. So, I (while still in X, which was maybe a mistake, read on) opened up /etc/dbus-1/system.d/hal.conf and changed 'plugdev' to 'users' in the below section:
<!-- Allow members of the 'plugdev' group to mount volumes -->
Saved the file off somewhere, then su-ed, made a backup of the original and copied the changed file to /etc/dbus-1/system.d/hal.conf. As soon as I did this, all windows (except Firefox, oddly enough) in my XFCE session closed, my XFCE desktop went from the default blue to black, and all the icons on it disappeared. The right-click application menu wouldn't appear either.
Figuring this to be bad, I did the Ctrl-Alt-Bksp thing, then completely logged out of X and restarted. Same problem.
I logged out of X again and from a console su-ed and replaced the modified hal.conf with the original. No good.
Next, I figured maybe the udev daemon needed to be restarted, so I did a kill -HUP on it.
Now I'm posting here from XFCE with my black, icon-less, application menu-less desktop wondering how in the world I could have broken things so badly (I was being so careful, dammit!
), and wondering what else I could try to fix them?