Found the answer from an earlier reply from JMC:
Found the solution. You have to delete/rename the *.nk2
or *.nick file from documents and
settings/username/application data/microsoft/outlook.
Thanks!
> When creating a new email message, I put a partial name in the "To:" field
> and outlook comes up with a list of suggested email addresses. However,
[quoted text clipped - 3 lines]
> but it still shows old email addresses. How do I sync this feature with my
> current contact list?
Russ Valentine [MVP-Outlook] - 03 Nov 2004 19:29 GMT
You don't really have to blow away your entire cache. You can just delete
the invalid entries using your Delete key when they are presented in the
suggested names list.

Signature
Russ Valentine
[MVP-Outlook]
> Found the answer from an earlier reply from JMC:
>
[quoted text clipped - 16 lines]
>> my
>> current contact list?