Move data from an old Mac to a new Mac | Operating Systems | Working Mac | Macworld: There are many reasons to get a new Mac—your old one is too slow, too ungainly, or it’s incompatible with the latest version of OS X. Regardless of why you’ve walked a new Mac through your front door, when you do, you face this immediate challenge: Moving the data on your current Mac to the new computer. There are multiple means for doing this. We’ll look at one built into Mac OS X—Migration Assistant.