I had NIS 2009 on a work computer, but its terrible memory leakage problem led me to eventually upgrade to NIS 2012 a few days ago.
Right after the upgrade, network file sharing on that pc has slowed way down. The daily file transfers across the network that used to take 5 seconds now require 5 to 10 minutes to complete. For years I have used batch files and XCOPY to transfer files across the network. The mappings are still present. I tested a batch file XCOPY on another computer that has no Norton products installed, taking the affected computer out of the process, and the file transfer went normally. The XP firewall is disabled as always.
I have uninstalled NIS 2012, but the networking is still slow as molasses. The internet works just fine as always.
If you need some stats on the computer, it'll have to wait until I go to the office where the pc is located - because my remote administration program that I've used for years just hangs now when I try to access the affected pc's desktop.
Ron