I am new to Outlook, so I am still getting my feet wet and trying to maximize
the program.

I work for a professional association that has a email contact list of
members of about 1500 different email addresses. When we get new email
addresses to add to our list, i need to be sure that they are not duplicates
of addresses we already have.

Any ideas on how to do this, without making a separate contact for each
email address in outlook? I tried an excel spread sheet, but that will not
notify me of a duplicate, it will only show me duplicates it I sort it
alphabetically.

For example, if I am adding " to the end of our list, and that
email address is already in the list toward the top, I need something that
will indicate to me that the address is already there.