After my upgrade to Ubuntu Jaunty 9.04 I’ve experienced a weird beahaviour of system-config-printer (which is the applet in System -> Administration -> Printing used to add printers and configure their default settings) consisting in the window stuck grey with 100% CPU usage and increasingly huge memory leak (>350Mb after 60 secs) (this is by python process since it’s simply a python script).

I’ve eventually figured out the issue being profile-specific and a workaround being the removal of a configuration file in your profile directory:

rm $HOME/.gconf/desktop/gnome/interface/%gconf.xml