Completely disable autocomplete in Mac Mail I use mail 8.2 on OS X 10.10.  Due to new corporate policy at my office, no autocompletion is allowed in e-mail clients (except maybe for address fetching from the corporate address book via exchange: it's not clear).  

Is it possible to disable either autocompletion entirely, or the addition of people to the autocompletion list?
May be this discussion will help you:
https://discussions.apple.com/thread/6861390?start=0&amp;tstart=0