... and Exchange 2003 stopped delivering messages to mailboxes.
Rolled it back, and everything worked fine ^H^H^H^H just as it used to.
I may be missing the point of these "fixes", but surely "security updates" should actually be tested at some stage?
"The number of Unix installations has grown to 10, with more expected." -- The Unix Programmer's Manual, 2nd Edition, June, 1972