What to do when switching to a Mac with a smaller drive Follow these steps to reduce your storage demands. Mac 911 Feb 25, 2021 7:15 pm PST IDG For reasons of cost, we might buy a new Mac with a smaller drive than the one we’re replacing. If your current Mac has more data stored than the capacity of the new one, you probably feel you’re in a pickle. But you can strategize how to make this transition work. When planning the transistion, I highly recommend that you try to keep free at least 50GB on a 256GB drive, and 100GB on drives that are 512GB and larger.