I am experiencing a significant slowdown when sharing files over a
home network. Here is the scenario:

5 computers: 3 have Vista sp2, 1 has Windows 7, 1 has XP sp3

All computers are running Norton Internet Security 2009.

1 of the Vista computers (host) is set up to share documents via the public
folder.

When the XP computer accesses shared files on the Vista computer, there are
no problems. But when using either the remaining Vista computers or Windows 7
computer to access the shared files on the Vista computer (host), there is a
significant slowdown. It takes a long time for the file to open. From what I
can tell, Norton is doing a full scan on the shared file before
it "downloads" it. For example, in Excel 2007 there is a status bar in the
bottom right corner while the file opening/downloading over the network.

If I disable Norton autoprotect the problem goes away, but obviously this
isn't the way to fix the problem.

I recognize this is probably an issue with Norton, or at least the way
Norton is interacting with Vista, but I have no idea how to fix it, other
than removing Norton and using another virus software. Contacting Norton has
gotten me nowhere.

All computers have the latest MS updates. I have tried uninstalling and
reinstalling Norton, with no success. I have also replicated the issue all
the other Vista computers, by setting them up as the "host" computer, to rule
a problem specific to the original Vista computer - same problem occurs.

Is there a way to fix this problem, or is it just a function of Norton and
Vista interacting poorly? Just to be clear, there are no issues when
accessing the internet via the same shared router. I also just added a Window
7 computer to the network, with Norton 2010, and the same problem occurs (the
file eventually opens after a long lag/once scanning completes).

Norton is the biggest anti-virus company out there. I just can't believe
this is a known issue that hasn't been fixed. So I'm hoping I'm doing
something wrong.

Thank you.