How To Fully Erase A Mac Using Recovery Assistant

by: Encryptor5000

Last modified: Sep 9, 2023 2:26 PM

28 2417 Last modified Sep 9, 2023 2:26 PM

In macOS Catalina and later, Apple introduced authentication requirements for accessing macOS Recovery. In particular, an administrator's password is required if FileVault or Activation Lock are enabled. The app that handles this authentication in macOS Recovery is Recovery Assistant.

Recovery Assistant mostly deals with authentication and password resets, but it can also erase your Mac if you ask it to. This process doesn't require a password, and it's especially helpful in these scenarios:

The Mac doesn't support Erase All Content and Settings.
Erase All Content and Settings finds an error that prevents it from working normally.
You just want to erase everything without dealing with Disk Utility or Terminal.

This erases everything!

Unlike Disk Utility or Terminal, Recovery Assistant doesn't offer a choice of what to erase. It erases everything on your Mac - including your files, apps, user data, settings, and macOS itself. If you installed Windows using Boot Camp Assistant or manually added other volumes or partitions, those will also be lost and reset.

IMPORTANT: Activation Lock remains and must be cleared afterwards to reuse the Mac. If a firmware password was set, that will also likely remain.

When Recovery Assistant erases a Mac, this happens behind the scenes (for technical readers):

Intel-based Macs: The internal disk is repartitioned and formatted (erased), or all partitions and containers except the EFI partition are deleted. A new APFS container is provided for macOS. After the erase, the Mac starts up from Internet Recovery, because local Recovery no longer exists.

Apple silicon Macs: All partitions or APFS containers are deleted, except for two critical system containers. A new APFS container is provided for macOS. After the erase, the Mac starts up from System Recovery (an emergency copy of macOS Recovery).

Why this method?

Disk Utility and Terminal provide more control, but it's also easier to perform unintended actions using those utilities. Many threads on this site have arisen because a user didn't erase the right item in the right way in Disk Utility, often leaving behind an old System or Data volume.

Recovery Assistant provides only one way to erase a Mac, and it's always a correct full erase.

Which Macs support this?

Any Mac running macOS Catalina or later (10.15+) can use this method. This includes all Apple silicon Macs - the oldest macOS to support them is macOS Big Sur (11.0.1).

NOTE: This may include some Intel-based Macs that support macOS Catalina but don't have it installed. In such a case, starting up from Internet Recovery (Option-Command-R) will likely download and boot a copy of Recovery that corresponds to Catalina and later.

Erase Your Mac Using Recovery Assistant

Before starting, please review these important steps:

Back up your Mac if possible. An erase cannot be undone.
If you enabled Find My Mac using an Apple ID, make sure that Apple ID is ready and available. You'll need it to clear Activation Lock.
Make sure you have a strong and fast Internet connection. You'll need it to reactivate your Mac and reinstall macOS.

Start up from macOS Recovery

Intel-based Macs: Hold down Command-R as you power on or restart your Mac. Release the keys when the Apple logo and a progress bar appear.

Apple silicon Macs: Shut down the Mac, then press and hold the physical power button until the message "Loading startup options" appears onscreen. Then, select Options and choose Continue.

NOTE: On Mac laptops, the built-in Touch ID button is also the power button.

Open the Recovery Assistant

If you're asked to authenticate as an admin, don't provide your password yet. Skip this section instead.

The recovery utilities should appear. From the top of the screen, select Utilities -> Terminal.

In Terminal, type "resetpassword" without the quotes and hit Enter (Return).

The Recovery Assistant app should now open. Click on its window title ("Reset Password") to bring it to the front.

Erase your Mac

Once Recovery Assistant is open, go to the top of the screen and select Recovery Assistant -> Erase Mac.

This screen should then appear. Select Erase Mac, then confirm again when prompted.

After the erase

Once the erase is complete, your Mac will restart. If it's an Intel-based Mac, connect to a supported Wi-Fi network when prompted. This is required to use Internet Recovery, and a spinning globe will appear.

If the Mac has an Apple silicon chip (M1 and later) or the T2 Security Chip, it will then show this screen:

To proceed, click the Wi-Fi icon in the top right and connect to a supported Wi-Fi network. Then, authenticate with your Apple ID and password to clear Activation Lock if required. Once done, exit to the recovery utilities.

Install macOS again!

When the recovery utilities appear again, select Install/Reinstall macOS and choose Continue. Then, follow the onscreen instructions to install macOS.

Once the installer is finished, the Setup Assistant will appear. If you're selling or giving away your Mac, stop and press Command-Q to shut down the Mac. This allows the new owner to complete the Setup Assistant using their info.

NOTE: Some versions of macOS Recovery might name the new startup volume "Untitled" after the erase. If this isn't desired, open Disk Utility before installing macOS, and rename the volume to something else (e.g. "Macintosh HD").