If memory serves, we only added a couple of exclusions to NAV 2002's default list. The XP Pro workstations were accessing both large and small files on a NetWare 5 server (using Novell's client). It just seemed to make sense that allowing NAV to scan files that could never be infected (and could be very large) would drag down performance. However, when users began complaining that their brand new workstations were slower than their old workstations, one test we did was to turn off NAV 2002. This solved the problem. Performance returned to normal. So then on a hunch, I turned NAV 2002 back on and set it for comprehensive scanning. Again performance remained normal. It made no sense, but we dropped the idea of exclusions after that.