Apple Mail

Yes I still use the simple and default OS X Mail app, Apple Mail. I'm too lazy to research better alternatives and it does the job for my basic mail needs. It works fine except for when I try to type a name in the To field when composing a new message. It tries to autocomplete a previously known address and with everybody changing email accounts, I can't remember which is the new default. The result is that I use the wrong account without knowing.

Rob and I were talking about this so I finally got around to googling the fix. Apple Mail has a Previous Recipients window which allows you to hunt down and kill these legacy addresses. If you still use Apple Mail like I do then its best to periodically check this for defunct addresses.