Click Time Machine from the options - if you don’t see the option you can click the Back arrow in the upper left or the series of boxes in the upper left, then select Time Machine. Next click the Apple Menu in the upper left and select “System Preferences” After the drive erases you can close the Disk Utility window. Click the Erase option near the upper right of the window, give the drive a name like “Backup” and then choose APFS as the format, and GUID Partition Map as the Scheme. Select the Drive you want to erase on the left side under the headline “External.” In the case of the Samsung T7 portable SSD drive you can choose the option that reads “Samsung PSSD T7 Media” at the top of the list of External. Click the View menu at the top of the screen and select “Show All Devices” or look in the screenshot below for this icon and click it, then select the same option. Once you’ve found it you can press the return key on your keyboard or double click on Disk Utility from the list of results.

Search your computer for Disk Utility - the easiest way is to click the magnifying glass (Spotlight) icon in the upper right of your computer and type Disk Utility.Once you have connected the new drive to your computer, follow these steps below. Optionally for a traditional portable hard drive you can also select the format Mac OS Extended (Journaled). If you already know how to use Disk Utility, the format information to choose is APFS or APFS (encrypted) and the scheme should be set to GUID Partition Map. Follow these directions to get your drive formatted for the Mac. The drive will be formatted HFS+, but installing macOS High Sierra or Mojave will change the format to APFS, assuming you’re installing on an SSD.Occasionally you may purchase a drive that comes pre-formatted for use on Windows and will need to erase it to use properly on the Mac. Disk Utility showing GUID option for drive formatĬlick Erase to wipe all the data that’s currently on the drive and reformat it for your macOS install. If you selected the drive name instead of its description you won’t see the Scheme option. Set the format to Mac OS Extended (Journaled) and the Scheme to GUID Partition Map. Disk Utility’s View option shows devices, not just volumes Select the drive description just above the drive name for the device you want to format. Now you should see your drive device descriptions with the drive name nested underneath. Disk Utility hides the GUID format option by defaultĬlick the View widget in the upper left corner of the Disk Utility window and choose Show All Devices. The app is hiding in the Utilities folder inside the Applications folder. Start by connecting the drive to your Mac. We’ll use an external drive for this example. Unfortunately, Disk Utility in macOS High Sierra doesn’t make that option easy to find.

Formatting a drive so you can install and boot macOS requires the GUID partition map.

Reformat harddrive mac