Norton security products are among the top three troublemakers for
Windows Mail. Symptoms often don't surface until several months have
gone by, or until an update occurs.
First, be sure to disable its email scanning, for the reason explained here:
http://thundercloud.net/infoave/tutorials/email-scanning/index.htm
Since I don't own a copy of Norton Antivirus, I can't tell you how to
navigate its menu.
Several users here have reported that Symantec will give you a free
upgrade to Norton Antivirus 2009, which may cure the problem. If
interested, contact Symantec via online chat.
Disabling the Norton program is often insufficient. If so, do a trial uninstall,
followed by using their debris removal tool:
http://service1.symantec.com/Support/tsgeninfo.nsf/docid/2005033108162039
Instead of uninstalling your antivirus, another option is to upgrade to
Windows Live Mail, which is more resistant to the adverse effects of overly
intrusive antivirus products:
http://download.live.com/wlmail
