How do I stop my outlook.com account from redownloading old emails to my Mac outlook program?

This problem started about a month or so ago.  I did not change any setting in my outlook program nor outlook.com account.  The account is shared by my wife and I so we have always left messages on the server so that we can both read them from our computers and our iPhones.  It has worked before.  When we did this when we had a wild blue.net email account, we had to add "recent" before our email name in our outlook setup but didn't have to when we transferred our email to outlook a few years ago.