Format a disk for Mac

During manufacturing, most external hard drives and solid-state drives are formatted for compatibility with Windows PCs. This isn’t a physical characteristic, though, and you can change it when you connect the disk to your Mac. If you plan to use the disk exclusively with Macs, there are benefits of reformatting it in the Apple format, known as APFS.

Note: This process erases everything on the disk, so it should be the first thing you do after buying it, before you start using it.

1. Connect the disk to your Mac.
2. Open Disk Utility. You can do this in any of the following ways:
• In the Dock, click Launchpad, open the group called Other and click Disk Utility.
• Click the Spotlight icon (magnifying glass, top-right of the screen), type “disk utility”, and double-click the search result for Disk Utility.
• Open Finder and go to Applications > Utilities, then double-click Disk Utility.
3. From the menu, choose View > Show All Devices.
4. In the sidebar, select the uppermost entry for the disk you connected. Be careful to choose the right one! Its name should reflect the manufacturer, like LaCie, Seagate or WD.
5. Click the Erase button in the toolbar.
6. For the scheme, choose GUID Partition Map.
7. For the format, choose APFS or, if you want to protect the disk with a password, APFS (Encrypted).
8. Type a name, for your own reference, that reflects what you’ll store on the disk — like “Old Photos” or “Backups”.
9. Click Erase – the process will take a few seconds – then click Done.