In 2013, we gave a good tip here at which explained exactly what you need to do before selling or donating your Mac.
Even though that article was written four years ago, it is still totally in line with today's reality. The tip, then:
- Create a backup of your computer (either through Time Machine, in the cloud or by connecting an external drive and dragging everything important to it);
- Deauthorize iTunes (by going to Account Authorizations Deauthorize This Computer);
- End the iCloud session and now the iMessage session as well.
These were the steps to be followed before erasing the contents of the machine and reinstalling the operating system itself. Now, after launching the new MacBooks Pro, Apple has included two extra steps: unpair Bluetooth devices and erase data from the Touch Bar.
Unpairing Bluetooth devices is optional. As Apple explained, this is a good option if you plan to keep these devices with you (a mouse, keyboard or anything else, to be used on your new computer) and if the sold / donated Mac remains in use in your home or that is, within the same area of the Bluetooth signal.
To unpair the devices, go to Bluetooth System Preferences, hover your cursor over the device you want to delete from the Mac, then click the “x” button to the right of its name.
But the novelty is the possibility to delete the contents of the Touch Bar. That's right, you can clear any information stored in it before selling or donating your MacBook Pro. What information is there that stays there? Nor did Apple explain, but before you ask, the Touch ID fingerprint reader (which is part of the Touch Bar) "records the information captured from your finger" on Secure Enclave.
Another curious fact of this new step added by Apple is that, unlike all of those described above, it can only be done via command in Terminal (there is no graphical interface to carry out this action). So, for that, you need to restart your Mac by pressing the R keys. When the macOS utility window appears, go to Terminal Utilities in the menu bar and enter the following command:
After pressing the Enter key, the system will ask if you are sure you really want to delete the content from the Touch Bar. Answer yes and then press Enter again. There, your Touch Bar is properly reset! Now exit the Terminal and proceed with the reinstallation of the system to sell or donate your Mac.
So, don't forget: if you have a MacBook Pro with Touch Bar, add this one more step when selling / donating your machine! 😉