Mail.app won't recognize a contact's name from my Address Book
I use Mac OS X Mail and have all of my work contacts in Address Book. When I receive email from one contact, the "From" field just displays his email address (as opposed to his first and last name) even though I have a contact card for him in my address book. For all other contacts, Mail displays their first and last names appropriately.
What's really weird is that if I hover over his address in the "From" field and click to bring up the context menu, there is an option for "Add to Address Book" (as if he doesn't have an entry), whereas for other contacts the option is "Open in Address Book." If I click "Add to Address Book," a new contact card is created for him even though I already have one with the same email address set up!
I've tried both assigning a first/last name to the duplicated card as well as merging the duplicated card with the original. In both cases, Mail "forgets" that the card exists and treats his email address as a new contact.
How do I get Mail to realize that there is, in fact, a contact card with his address?
Choose the Window > Previous Recipients menu item in Mail, and see if the email address is listed there without a first and last name. If so, try adding the email address to Address Book and merging the new entry with the existing one. In Address Book, one method of merging contacts is to select both entries and choose the Card > Merge menu item.
If I got it right, you are having troubles with ONE certain e-mail address. Just searching for possible reason - have you tried to 'Add to Address Book' and then assign some different name/last name? Just for test? Will mail recognize it then?
Then, did you check if Address Book actually keeps this particular contact in the account which you set as default (check General Tab in Preferences in Address Book)? Perhaps it saves it in some network service? Like Exchange server? Is this default account actually enabled?
If everything is in order then we'll search further :)
UPDATE on Dec 15, 2014
Looks like I had similar situation just now :) What I did: I right clicked on the address and chosed 'Edit Address' and right in the field entered first and last names. After that I have removed old record from Previous Recepients list.