Preparing and Wiping Your Mac for Sale

It’s a hard decision to make, but if you decide to sell the Mac you became attached to over the past few years – whether it’s going to a stranger or a good friend – there are some recommended steps to follow to protect the personal data saved on that device. It is essentially a ritual to prepare it for sale or when giving it away.

Step 1: back it up

Assuming that you already have the new Mac to hand before selling the old one (unless you want to switch to Windows), use the neat in-built feature Time Machine to save and transferall the data from the old Mac to the new one. If the computer is not around, well, don’t sell your old computer just yet, as you never know when you’ll need.

Step 2: sign out of everything

You won’t even realize how many Apple services have been logged into until the sign out process. Just consider how macOS comes pre-installed with iTunes, iMessage, and iCloud, as well as essential services such as Find My Mac. In order to protect your privacy, sign out of all these services before you move on to the next phase.

a) To sign out of iTunes open the app and, from the top of the iTunes window, choose Accounts Authorizations > Deauthorize This Computer. Enter your Apple ID when prompted, and click “Deauthorize”.

b) For iMessage launch the software and click “Command + ,” to launch Preferences, then select Account > Sign out from the selected account.

Step 3: use a Mac optimization app to securely erase sensitive data

With the iCloud data removed from the hard drive, you should make sure that no one can recover your private data using a data recovery tool. That’s the purpose of the secure erase or shredder features built into Mac optimization apps. If you have apps such as CleanMyMac or OnyX handy, just select the folders that need to be erased for good and drop them into the dialog box. This way the most important and private data is definitely removed from your system. If FileVault has been used to encrypt your SSD the new owner would need the key to decipher that data, so you can skip this step.

Step 4: reformat your startup disk

After the data erasing process is finished, there is one more erasing step required before you move on to the clean install. The startup disk needs to be reformatted, because just signing out of Apple services and erasing private data is far from enough to prepare your old Mac for sale. To do so, follow these steps:

1. Restart your Mac.
2. Press and hold down the Command + R button right after restart until you see the Apple logo.
3. macOS Recovery will appear, where you should select Disk Utility from the utilities window, and click continue.
4. Select your startup disk in the sidebar of Disk Utility.
5. Click “Erase”.

At this point you’ll be required to completely setup the Mac once again so it is ready to use by its next owner. Enter the following details:

1. Name: enter a name for the disk.
2. Format: choose Mac OS Extended (Journaled).
3. Scheme (if available): select GUID Partition Map.

The formatting process can now be finalized:

1. Click on the Erase button to begin the formatting process.
2. Once Disk Utility has finished formatting the disk, quit the app and return to the utilities window.

Step 5: reinstall macOS

Now you will need to perform a clean macOS install following the steps below:

1. From the macOS Recovery window, select “Reinstall macOS” (or “Reinstall OS X”).
2. Click Continue, and follow the onscreen instructions.
3. Select your Startup Disk, and click “Install”. If you are prompted for your Apple ID, just ignore the prompt.
4. Wait for the Mac to restart after finishing the installation and a setup assistant will appear.
5. Press Command + Q to quit the setup assistant without performing any of the setup steps. Let the new owner complete the setup process with his or her own Apple ID.