You should see a list of available drives. Open Applications > Utilities, which is found through Finder, then open the Disk Utility application. There are several options which we will look at to help you choose the correct format for you and show you how to ready the disk for use Step 1: Launch Disk Utility Formatting an external drive for use with an Apple Macīefore you can use a new (or old) drive with a Mac you will need to format it.