Locate (but don't yet click on) Macintosh HD in the sidebar underneath the Internal heading.

If requested, enter the Apple ID and password that was most recently used with the Mac you're resetting.Press and hold the power button to turn your Mac back on, and continue to hold the button until you see a window with startup options.Follow the on-screen instructions to reinstall macOS on the factory-reset MacBook or Mac.To start back up and reinstall macOS, click Reinstall macOS in the utilities window.Exit the Disk Utility menu when you're done.Once the erase process has completed, repeat these steps for any other disk volumes under the Internal heading (you'll only have these if you previously added disk volumes using Disk Utility).If you have a button called Erase Volume Group, click it.The Format drop-down menu should say 'APFS' or 'Mac OS Extended (Journaled).' This is based on system recommendation, so you can leave it as long as one of the two is showing up there.Make sure the Name section says 'Macintosh HD.'.Once you have selected the drive, click Erase in the toolbar.If you don't see Macintosh HD or your chosen disk name, shut down your computer, unplug all external devices (you can leave things like mouse and keyboard plugged in if necessary), and start these steps over.Select Macintosh HD in the sidebar underneath the Internal heading (or the name of your disk if you've changed its name from Macintosh HD).Turn on your Mac, and while the Mac is restarting, hold down the keyboard combination cmd+R until you see the Mac logo or another icon or image appear.Here's how to reset Macs with Intel chips and reinstall mac OS if you choose to do so:

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