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SteveHS Author

Level 1

8 points

SecureErase (Category 4 - DoE 3 - Pass Secure Erase) Macintosh HD - in Terminal app

iMac -2012 - MacOS Catalina

I want to secure-erase my entire HD, not just the free space. The end goal is to sell my computer

I entered all of the required information into terminal to activate a category 4 secure erase.

After hitting the enter key, a line appears stating: "Ownership of the affected disk is required."

My question: What ownership information is required to activate the category 4 secure erase process?

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Below is a copy of all of the information displayed in the active Terminal window:

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Last login: Wed Oct 19 22:47:31 on ttys000

[—————— @ ———— iMac ~ % diskutil secureErase 4/Volumes/Macintosh\ HD]

Usage: diskutil secureErase [freespace] level

MountPoint | DiskIdentifier | DeviceNode

"Securely" (BUT SEE "man diskutil" FOR MODERN LIMITATIONS) erases either a

whole disk or a volume's freespace. Level should be one of the following:

0 — Single-pass zeros.

1 — Single-pass random numbers.

2 — US DoD 7-pass secure erase.

3 — Gutmann algorithm 35-pass secure erase.

4 — US DoE 3-pass secure erase.

Ownership of the affected disk is required.

Note: Level 2, 3, or 4 secure erases can take an extremely long time.

—————— @ ———— iMac ~ % []

iMac

Posted on Oct 19, 2022 11:41 PM

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43 replies

HWTech

Level 9

56,408 points

Oct 24, 2022 6:45 AM in response to SteveHS

SteveHS wrote:

These are the results from the (2) recently suggested parameters spacing (in recovery mode)::

[-bash-3.2# diskutil secureErase 4 /Volumes/Macintosh\HD

Could not find the disk /Volumes/MacintoshHD

You missed the space between the backslash and the "HD". Normally a space is a special separator character so the backslash basically tells bash that the space following the backslash is meant to be part of the same option/entity which in this case is a path. Without the backslash, the space indicates to bash that another option for the command is present.

https://linuxhint.com/deal-spaces-file-path-linux/

[-bash-3.2# diskutil secureErase 4 "/Volumes/Macintosh HD"

A whole disk must be specified when doing secureErase without the

"freespace" option; if you need to wipe a single partition, you must

use diskutil zeroDisk or diskutil randomDisk but you will subsequently

need to reformat (newfs) the partition with "diskutil eraseVolume"

[-bash-3.2#

I was wondering about this command requiring the whole drive. Seems the whole drive must be erased when performing the secure erase unless choosing the erase free space option. Like I mentioned earlier, very few people on these forums tend to use some of these less used and more obscure options and the Apple documentation is not always clear.

SteveHS Author

Level 1

8 points

Oct 24, 2022 12:34 PM in response to BobHarris

Having provided all of the essential information about my system and situation, is it possible to reach a reasonable consensus regarding the best way to move forward.

Is simply re-installing MacOS Catalina (over-writing the current MacOS operating system) sufficient considering the fact this system is operating off of an SSD?

Additionally, will I have the option to select the operating system via an online connection or would it be easier to access MacOS Catalina from my USB device? Please note: I will require instructions on how to boot into a USB device assuming this is an easier, considerably less convoluted method.