It's usually that way for me before it finishes starting up, which tend to
take around a minute.

Most versions of the Norton antivirus software eventually cause problems
in Windows Mail, but this usually takes months.  If you want to eliminate
that possibility, you have to uninstall it, since for most versions, either
turning off email scanning isn't possible, or it doesn't help, and disabling
the
program doesn't help either.  You then often need to run this program to
clean up what the uninstall left behind:

<http://service1.symantec.com/SUPPORT/tsgeninfo.nsf/docid/2005033108162039>

Sometimes you even have to remove your email account under Windows
Mail, then restart Windows Mail and add the account again.

If this cures your problem, you may want a replacement antivirus program
that doesn't cause such problems.  Most versions of the McAfee antivirus
program and a recent version of the Trend antivirus program are bad choices;
they cause problems in Windows Mail too.  I recommend either avast! or
AVG, either one with a custom install that tells 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