What do you do with an older Mac that still has your personal data on it? Are you getting ready to sell your used MacBook Air or MacBook Pro? Or do you want to give away or donate your MacBook to charity but also want to be sure not to leave a trace of personal data on it? Though most charities, like the Giving Center, wipe all incoming computer donations, here is a quick guide on how to reset a MacBook, or any Mac computer for that matter, to give you peace of mind.
Don’t let this seemingly daunting task keep you from giving away or donating your older Macbook. Though it may seem complicated, it is not hard to completely factory reset your MacBook (or iMac) and reset it to a like-new state. These instructions (with a few minor changes here or there) will work for macOS Catalina and most older versions of the operating system.
Make Sure You Have a Backup
Make sure that any important data on the hard drive has been moved or saved somewhere else. With a local backup copy and secure cloud storage, you know your data will be always safe no matter what happens.
Also make sure to sign out of iMessage, iCloud, and any other accounts you may have before you reset.
Once you have verified your data has been backed up, it’s time to get to work. The key thing here is OS X Recovery — a special part of the Mac operating system since OS X 10.7 “Lion.
What Type of Drive Do You Have?
Before we can start, you will need to know whether you have a HDD or a SSD. You can click on the Apple menu and select “About this Mac” to find out. From that menu, select the “Storage” tab to find out which type of drive is in your particular system.
For example, it can show a SATA Disk (HDD) in the system, or a Solid State SATA Drive (SSD), plus a Mac SuperDrive.
How to Wipe a Mac Hard Disk Drive (HDD)
- Start with your Mac turned off.
- Press the power button to turn it on.
- Immediately upon starting, hold down the command and R keys.
- Wait until the Apple logo appears.
- You will need to then select “Disk Utility” from the OS X Utilities list. Click Continue.
- Select the disk you would like to erase by selecting it in the sidebar.
- Select the Erase button.
- Click on the Security Options button.
- The Security Options window will include a slider that enables you to decide how thoroughly you would like to erase your hard drive.
There are four notches on the Security Options slider. The “fastest” will be quick but insecure — your data could potentially be retrieved using a file recovery program. Moving the slider towards the right will introduce progressively more secure erasing. The most secure level of the Disk Utility’s options erases the information used to access files on your disk and then writes zeroes across the disk surface seven times to remove all traces of what was there before. This option follows the DoD 5220.22-M specification. This level is recommended when selling or donating your MacBook.
Once you have selected the level of erasing security you are comfortable with, click on the OK button.
Begin by clicking on the Erase button. Keep in mind that the more secure the option you select, the longer it will take. The most secure methods can potentially add hours to the process.
Once this process is done, the hard drive will be clean and ready for the next step: a fresh installation of OS X.
After that, your Macbook will be ready for its next adventure; being donated to a relative or charity, like Giving Center, being sold, or sent to an e-waste facility.
Securely Erasing SSDs, and Why Not To
Most new Macbooks ship with solid-state drives, or SSDs for short. Only the iMac and Mac mini ship with regular hard drives now, and even those are available in an SSD variant.
If your Mac comes with an SSD, Apple’s Disk Utility software will not let you zero the hard drive.
On one tech note posted to Apple’s own online knowledgebase, Apple explains that you do not need to securely erase your Mac’s SSD:
Some people may tell you not to zero out the data on an SSD. This can cause wear and tear on the memory cells. Over time, this can affect an SSDs overall reliability. This may not be nearly as big as an issue as it used to be — SSDs reliability and longevity have greatly improved over the years.
If the “Standard Erase” does not make you feel comfortable, there are a couple of other options.
Securely Erasing Free Space on Your SSD
If you do not want to take Apple’s word for it or if you just want to, there is a way to securely erase free space on your SSD. It’s a little more complicated but it works.
For the record, this really isn’t necessary to do, which is why Apple’s made it hard. But if you are set on it, you will have to use Apple’s Terminal app. Terminal gives you the command line interface access to its OS X operating system. You can find Terminal in the Utilities folder as well as in the Mac’s Recovery System. Once your Mac boots into the Recovery partition, click on the Utilities menu and then select Terminal to launch it.
From the Terminal command line, type:
diskutil secureErase freespace VALUE /Volumes/DRIVE
This will tell your Mac to securely erase the free space on your SSD. You will need to change VALUE to a number between 0 and 4.
- 0 is a single-pass run of zeroes;
- 1 is a single-pass run of random numbers;
- 2 is a 7-pass erase;
- 3 is a 35-pass erase;
- 4 is a 3-pass erase
DRIVE will need to be changed to the name of your hard drive. For example, to run a 7-pass erase of your SSD drive in “JaneS-Macbook”, you would enter the following:
diskutil secureErase freespace 2 /Volumes/JaneS-Macbook
Keep in mind, if you use a space in the name of your Mac’s hard drive, you will need to insert a leading backslash before the space. For instance, to run a 35-pass erase on a hard drive called “Macintosh HD” you enter the following:
diskutil secureErase freespace 3 /Volumes/Macintosh\ HD
Another thing to remember is that the more comprehensive the erase procedure, the longer it will take.
