I had a significant failure with my two e-mail applications, Microsoft Exchange and Apple Mail. The problem started when a friend of mine retired from his job and I was told that I can no longer send him any e-mail to that business e-mail address. I deleted his entry in my computer for that business address. But, that was not the complete solution. The problem with Microsoft Exchange and Apple Mail is when I wanted to send my friend an e-mail, I was presented with his home e-mail address and his business e-mail address. Why? The reason is that both mail applications, it seems, scans all the prior e-mail from my friend to find all his addresses. These applications, it seems, fail to ONLY pull up the address from Contacts. The solution that I came up with was to use both e-mail applications and do a search for all the mail from my friend. I then selected only the e-mail that was addressed to his work and deleted all those messages. As a check, I performed a search for my friends name and Mac Mail was ok but Exchange was not. Exchange showed a small warning that more e-mails could be on the server. Exchange allowed me to view those messages and I deleted them. That seemed to be the solution. It would be really nice for those e-mail applications to include an option to only show addresses to people that are within my Contacts application. Now I did discover that Mac Mail does have an interesting option. Go into Mac Mail > Settings > Rule > then make a rule to delete any e-mail from the person. Next shows the menu options and correct answers:
If any of the following conditions are met: From contains E-mail address of person.
Perform the following actions: Delete Message.