Without any detailed information like version of Outlook and types of
configured account(s) it is hard to tell. Usually the cause is that the
connection to the server is not properly closed so Outlook doesn't mark it
as a succesful send/receive and collects the messages again at next
send/receive interfall. The not properly closing of the connection to the
server is most likely caused by an improperly configured firewall or
mailscanners (anti-virus/spam) that integrates with Outlook. See the
documentation of your virusscanner, spamfilter and/or firewall on how you
can disable them and see if Outlook behaves correctly now.
--
Robert Sparnaaij [MVP-Outlook]
www.howto-outlook.com
Tips of the month:
-FREE tool; QuickMail. Create new Outlook items anywhere from within Windows
-Properly back-up and restore your Outlook data
