The standard behavior for the Outlook Address book is to display all
electronic addresses (both fax and e-mail). That behavior cannot be changed.
The only way to prevent the display of fax numbers is to store them in a
different field or to disguise them (e.g., precede them with an alpha
character) so that Outlook won't recognize them as phone numbers.
There are also a number of utilities available that can do this for you
automatically. Some are listed here:
http://www.slipstick.com/contacts/nofax.htm

When you type a name in the To: field, you invoke autocompletion. It usses a
cache derived from messages you have already sent, not your Contacts Folder.

Outlook shows both the fax numbers (where present) as well as the email
address when addressing an email. I understand that this was so you could
send a message via either transport depending upon your contact. Therefore
if you have multiple fax numbers or emails then the contact will appear
multiple times when addressing emails.

However, if you do not use fax on your system, then having the fax address
displayed becomes a nuisance. Both because it displays an entry in the
addressing dialogue window for each fax number configured as well as the
email address, and when you expect Outlook to resolve the name
automatically it does not know which of the addresses for that contact you
wish to use - showing the squiggly red line.

It is possible to suppress the fax entry in the address dialogue by
prefixing the Fax Number for the contact with a non-numercal character or
string e.g. Fax: 01234 345 678.

If you have a number of entries to manage in this way, then you may wish to
consider an add-in that will automate the task and allow you to select such
as that found at
http://www.websetters.co.uk/WSAddIns/Fax%20Display%20Manager/Index.htm

It resolves these issues by managing your contacts, hiding the fax entry
when addressing emails but still showing the details in the contacts folder.

Regards
Graeme
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