Before selling a Mac there are a few things we need to do. First make sure that the Activation Lock feature is not activated and then reset the system
Before selling any used electronic device we should reset it to factory settings, erasing all data and all custom settings we have applied over the months or years. And the reason why is easy to say: by reselling a smartphone or a PC without resetting it, we would also "give away" our personal data stored inside the memory.
The operation, in the end, takes about ten minutes at the most, but it allows us to protect our privacy and our personal data. In some cases, however, you may need to spend a little extra time on it. If, for example, you're wondering how to reset Mac before selling it, know that you'll first have to disable some security features that protect your bitten apple computer in case of theft or loss of the device. If you should forget to do this, those who buy the used Mac may never be able to use it.
Why resetting new Macs is more complex
The "fault" is the T2 security chip, which has been installed in the bite apple computers since 2018. This chip was introduced on the iMac Pro from January 2018 and, gradually, on all other PCs (desktops and laptops) designed in that of Cupertino. The functions of the T2 chip are the most varied: in addition to managing various hardware components of the device, it takes care of encrypting all the information on the hard drive, so that it will not be readable if someone managed to get hold of the computer and, therefore, the hard drive.
In addition, the T2 chip also manages login information and stores it securely. This feature, called Activation Lock, ensures that the MacBook or iMac will only boot up if the Apple ID credentials are entered even if the device has been restored to its initial settings. A security feature, which prevents hackers or simple thieves from accessing the device in case of theft, but can create some headaches for you when you want to sell the PC.
How to disable Activation Lock Mac
Disabling Activation Lock, fortunately, does not require much knowledge or effort. First of all, let's make sure that it is activated. Click on the bitten apple icon in the top left corner and then on About this Mac. Here, choose System Reports and look for the "Activation Lock" line - you'll find out whether the feature is enabled or not.
If it's enabled, open Computer Settings, click Apple ID and then iCloud. Search for Find My Mac and uncheck it. Now log out your Apple ID and the feature will be permanently disabled.
How to Reset Mac
Now you can proceed with resetting your Mac to factory settings. Restart your computer and as soon as you hear the sound of the system starting up, press the "Command" and "R" keys and hold them down until the bitten apple logo appears. After a few seconds, Recovery mode will be launched. Here, choose Reinstall MacOS: the system will initialize the disk and start downloading the latest version of the operating system and then install it from scratch.