Member Avatar for Patryk_1

I am selling this 5 year old Mac through online. But before that, I am looking to wipe all its data to an extent where it is unrecoverable. The only question is how should I make sure if my Mac is wiped beyond recovery.

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Good follow-up from — and useful context from and . The right way to make your Mac’s drive “unrecoverable” depends on the hardware (spinning HDD vs SSD/Fusion/NVMe) and the Mac model / macOS version. For modern Macs with Apple Silicon or the T2 chip, Apple provides a fast, built-in erase flow that effectively renders user data unreadable; for older spinning disks, overwriting remains an option. (support.apple.com)

Practical choices (short workflows):

  • Apple Silicon / T2 Macs (monterey or later): use System Settings → General → Transfer or Reset → Erase All Content and Settings (this signs out iCloud, removes Activation Lock, and performs the recommended secure wipe for these Macs). (support.apple.com)
  • Macs without that option or when manually erasing: start in macOS Recovery, open Disk Utility, select the physical device (View → Show All Devices) and Erase the whole disk. If the disk is an SSD, enable FileVault first or rely on the Secure Enclave/media-key removal — that makes leftover bits cryptographically inaccessible. (support.apple.com)
  • Older mechanical HDDs you want repeatedly overwritten: use Disk Utility’s Security Options if available, or the Terminal command diskutil secureErase on a non-startup drive (example below). Always double-check the disk identifier — wiping the wrong disk is irreversible. (support.apple.com)

For maximum assurance (very sensitive data): NIST accepts cryptographic erase when strong encryption was used and the keys are destroyed; it also recommends physical destruction when absolute certainty is required. If the data is highly sensitive, arrange secure destruction through a certified recycler or physically destroy the drive after removing it. (nvlpubs.nist.gov)

Quick Terminal example (mechanical, non-startup disk — replace /dev/diskX with the correct disk):

diskutil secureErase 0 /dev/diskX

Final checklist before transfer: back up, sign out of Apple ID/iCloud/Find My, deauthorize services, erase and reinstall macOS, and leave the Mac at the setup assistant screen. (support.apple.com)

Key references:

  • Apple: Erase your Mac and Erase All Content and Settings (support.apple.com/102664).
  • Apple: Disk Utility guide (support.apple.com/guide/disk-utility/dskutl14079/mac).
  • Apple: FileVault / Secure Enclave details (support.apple.com/guide/security).
  • NIST SP 800-88: Guidelines for Media Sanitization (nvlpubs.nist.gov).

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Member Avatar for Patryk_1

@tom what is the difference between 3 and 7 passes?

Member Avatar for tompatrick

Disk utility overwrites the sectors of the hard disk drives using 0s and 1s. 3 Passes indicates that disk utility will overwrite the location with binary numbers in three times. Similarly 7 passes overwrites the location seven times. All these efforts are made to make sure that no data is left out on the drive which can be recovered using a file recovery software. In my above post I told you that Disk Utility will not wipe it's own startup drive since you cannot erase the drive from which OS X have been booted. You have to make a bootable dvd to start the Mac and erase your Mac OS X hard drive. Hope this info helps.

Member Avatar for Jesshillips

Macintoshes hold their worth extremely well, and it frequently bodes well to offer yours to help pay for the new model you are pining for. On the other hand you may be feeling liberal, and you need to hand it down to somebody destitute. One inquiry rings a bell.

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