Comment 32 for bug 293535

I had similar symptoms under lucid while trying to change my window manager to sawfish--one CPU pegged at 100%, with top showing gconfd-2 using up about 20% and Xorg about 15%. It turns out that the problem was caused by metacity trying to start, realizing that another window manager was running, outputting and error, then being RESTARTED very quickly. "top" didn't list metacity as the culprit because each metacity process was dying so quickly that it didn't show up in the statistics. It was gnome-session that was restarting metacity endlessly, so I suggest that this is a bug in gnome-session (it should somehow give up after a while, and probably show an error dialog).

I described the solution for my problem (which doesn't necessarily apply to this bug) in bug #453115.