With the release of El Capitan, Apple took the opportunity to give Disk Utility a facelift. You can still use the software to format a startup drive—it’s similar to the steps in the previous version.
This how-to goes through the steps of formatting a startup drive using Disk Utility 15 in El Capitan.
1. Connect your drive
To format an external storage device, connect it to one of the ports on your Mac. Turn the drive on, and make sure it appears in the Finder.
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