• How To Wipe A Mac Hard Drive

If you use a traditional hard drive with OS X 10.11, and are comfortable with the command line, you can use the Mac's srm command to overwrite the file. Fuller instructions (in English) are available here. Srm was removed in OS X 10.12, but it is still possible to install. In the latest versions of macOS, you can use rm -P to overwrite the file. Whether you want to clean a disk or wipe disk free space, ShredIt for Mac OS X is the right security eraser software for the job. Secure Delete files, disk free space, a hard drive, an external drive, a CD-RW and more. It comes with simple instructions, built in safety features, DoD, DoE, NSA, Gutmann standards compliance and online tutorials.' Mac users having already deleted files and needing to ensure those deleted files are unrecoverable can take the extra step of securely erasing free disk space. To securely erase free disk space. There’s just one last bit of information you need to know to erase the free space on a hard drive from the command line. In Unix, all devices appear as part of the file system tree, and in macOS.

If you are planning to sell your Mac or giving it to a third person for permanent use, then you must erase the hard drive first. This is how you can prevent your data falling into wide of the mark hands.

In case, you are using a newer Mac with an SSD, then you have to take extra care.

You can easily ensure in several ways that data saved on your traditional hard drive is securely deleted. But, they do not really help if you have an SSD. As your SSD won’t fall into the category of a hard drive.

AboutSecurely Erasing SSD:

If your Mac comes with an SSD, Apple’s Disk Utility won’t let you to securely erase the SSD. Yes, Secure Erase and Erasing Free Space options are not available in Mac Disk Utility.

People say these options are not required for an SSD since a standard erase itself is enough potential to make SSD data recovery hard. And, some says securely erasing an SSD, can cause wear and tear on its memory cells which affect the drive’s reliability and performance.

Leaving all these discussions, if you just want to securely erase free space on your SSD then here are two different ways you can try.

Before you getting started with it, let me tell something that “this is not really needed; as Apple itself made so hard to secure erase an SSD. But, if you are set on it then, give a second thought to your mind and proceed.

How to Securely Erase a Mac SSD?

Tone 2 electra2 dmg. Method 1: Steps to Securely Erase a Mac SSD from Terminal

Step 1: Open Applications folder and switch to Utilities folder.

Step 2: Run the Terminal application.

Step 3: Type diskutil secureErase freespace VALUE /Volumes/DRIVE and hit Enter key

Note: Type a number between 0 and 4 in place of VALUE. 0 for single-pass run of zeroes, 1 for single-pass run of random numbers, 2 for 7-pass erase, 3 for 35-pass erase, and 4 for 3-pass erase. Replace DRIVE with the name of your SSD. To run a 7-pass erase in “Peters-Macbook”, use diskutil secureErase freespace 2 /Volumes/Peters-Macbook code.

And if, there is a space in the name of your drive, use a backslash instead of each space (for instance to denote Mac Drive -> Mac Drive).

Method 2: Steps to Securely Erase a Mac SSD Using Disk Utility

Step 1: Reboot Mac, hold the OPTION key and select Recovery partition.

Step 2: Next, in OS X Utilities menu click on Disk Utility.

Step 3: Select the SSD primary partition and choose Erase option.

Step 4: Under Format, opt for Mac OS Extended (Journaled, Encrypted).

Step 5: Hit Erase button, and set encryption password.

Step 6: Wait till your drive gets erased and encrypted. It takes time, depending on type, size, and speed of the drive.

Step 7: Next opt Disk Utility and choose Mac OS Extended (Journaled).

Now, Erase Free Space and Security Options are accessible (they are not grayed out).

Step 8: Click on Security Options and select 35-Pass Erase.

How To Wipe A Mac Hard Drive

Step 9: Hit the OK button and wait until completion of the process.