Hi, I'm curious to know what's up with this situation. I have a new installation of WPMU 2.8.6 (with BuddyPress) and I'm setting up my main blog. I changed the category "uncategorized" to "announcements" but the URL when displaying that archive still reads /uncategorized/.
I tested this with other categories, first making them, then changing their names. The same problem occurs.
I searched the Trac system to see if this had been reported and I found this ticket describing the exact problem:
http://trac.mu.wordpress.org/ticket/476
This ticket however, claims that the issue was fixed two years ago :-/
Can anyone provide more info about this?