Make sure to select the parent hard disk in the sidebar.

When the process is complete, press command+Q to close Disk Utility.

Change the format to Mac OS Extended (Journaled).

Choose a new name for your Mac’s hard drive.

Click the Erase button at the top of the window.

If you don’t see it, go to View > Show All Devices.

Select your new hard drive from the sidebar.

How do I use Disk Utility to reformat my hard drive? Otherwise, you can skip this step and do it from the Utilities page during the macOS or OS X installation. If your Mac doesn’t work, you can do this using a second Mac and an external hard drive caddy. It’s easy to reformat your hard drive using Disk Utility in macOS or OS X. Disk Utility can be used to format external drives as well. If you don’t want to lose data from your hard drive, export the data or back it up before continuing. You may need to reformat your new hard drive before installing macOS or OS X on it.

macOS could not be installed, how-to fixįormat your new hard drive for macOS or OS X.

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Factory reset MacBook Air and other Macs with macOS.

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Or use the OS X installation disc that came with your machine - or buy a new one - to boot up and install OS X on your Mac’s hard drive.

Download the relevant macOS or OS X installer from Apple, then use Terminal to create a USB installer you can boot up from.

Install macOS or OS X from Internet Recovery Mode, which you can boot into by holding option+command+R while your Mac powers up.If you’re tech-savvy but don’t know where to start, use these Quick Tips to point you in the right direction for getting macOS or OS X on your drive: How do I install OS X on my hard drive using an installation disc?.How do I use a bootable USB installer to install macOS or OS X?.How do I create a bootable USB Installer?.Which version of macOS or OS X should I create an installer for?.Create a bootable USB installer for macOS or OS X.How do I use Internet Recovery Mode to install macOS or OS X on my hard drive?.Install macOS using Internet Recovery Mode.How do I use Disk Utility to reformat my hard drive?.Format your new hard drive for macOS or OS X.

Macbook air reformat