Most versions of the McAfee antivirus program tend to cause
problems in Windows Mail, although seldom immediately. Just
disabling part or all of the McAfee program seldom helps; you
usually have to uninstall it instead. You often then need to run this
cleanup program to take care of what the uninstall leaves behind:
<
http://service.mcafee.com/FAQDocument.aspx?id=107083&lc=4105&partner=McAfee&type=TS&ia=1>
You may then need to remove your email account under Windows
Mail, then restart Windows Mail and add the account again.
After that, click on the Outbox and move any messages you find there
to the Drafts folder or delete them. If any refuse to do either, download
and install this hotfix with Windows Mail not running:
http://support.microsoft.com/default.aspx/kb/941090
Although it's labelled as for mail stuck in the Outbox, it also works in
other folders. If you don't know whether you have a 32-bit version
of Vista or a 64-bit version, try the hotfix for the 32-bit version first.
The Vista SP1 update includes this hotfix and more, but takes longer
to install.
If this solves your problem, you may want a replacement antivirus
program that doesn't cause such problems. Most versions of the
Norton antivirus program and a recent version of the Trend
antivirus program are bad choices; they also cause problems in
Windows Mail. I recommend either avast! or AVG, either one with
a custom install where you tell it to leave out the part that scans email.
http://www.avast.com/eng/avast_4_home.html
http://free.grisoft.com/ww.download?prd=afe