How do I stop duplicate emails going into the inbox?

[IDA Dave]

I have a user that just started getting hundreds of copies in his inbox.
They are all legit emails but they keep coming. He might have ten new emails
and get over 500 duplicates. How can I fix this and have the user stop
getting all of these copies?

 

[Roady [MVP]]

See http://www.howto-outlook.com/faq/duplicates.htm