Disable OS X and IOS Contact Email Suggestions to Clear Recipient Field
One of the new features in El Capitan and iOS 9 is Proactive, which supposedly helps you automatically find email addresses and other information. However, this does not always work well. Fortunately, Macworld points out where to turn it off.
Proactive is supposed to automatically scan emails to pull in contact information to make it easier to communicate with people. Sometimes this is useful, but other times it just suggests email addresses from some random person you don’t care about, or worse, pulls out old emails for people for no apparent reason. For example, when I type my name, Mail offers eight different email addresses, including ones I haven’t used since college. To clear that up and let Mail only suggest emails from your real contacts, you just need to toggle a couple of settings.
On Mac
Launch Contacts, then go to Contacts> Settings> General. Uncheck the box next to Show contacts found in mail.
On iOS
Go to Settings> Mail, Contacts, Calendars and uncheck the Contacts found in mail box.
If these settings are disabled, the only automatically suggested recipients will be the email addresses that you have in your address book.