This happened to me also. I have confirmed it is a problem with Edgy and not GParted here: http://bugzilla.gnome.org/show_bug.cgi?id=357384 A workaround is to specify the drives manually. (For instance: gparted /dev/sda /dev/sdb) -- Gparted doesn't recognize partitions properly https://launchpad.net/bugs/54211