Once you’ve opened Time Machine, you’ll need to select the external drive you want to back up to. You should know that to make the copy safely and without risk, there must be enough space on the selected external drive, it is even recommended that there be something more than what it marks. To better secure the copy, click on the box that says “encrypt backup copies”. Once you have selected this option, all you have to do is hit “use disk” and wait for the copy to be made.
Sign out of iCloud and iTunes
Although it seems obvious, you need to sign out of iCloud and iTunes. In these apps, a lot of relevant information remains that is necessary to eliminate if you are going to sell your computer. In addition to removing your account, iTunes offers the ability to remove access to the account from that device. To do this you only have to press the menu. Once there, you will have to go to the gutter first and then to authorizations. The option to “remove authorization from this computer” will appear. This will ensure that your account is never reconnected.
To sign out of iCloud, simply go to iCloud System Preferences and sign out of the device. You must not forget either sign out of iMessage, which is another application in which some of your data is recorded. To log out of this app, you must access the application and in the upper bar click on Messages, then Preferences and finally “log out”
Unpair bluetooth devices
Also unlink those Bluetooth devices that you have linked to the Mac. An example of this can be the mouse or wireless headphones such as AirPods. This is unlinked from System Preferences, in the Bluetooth section and on each connected device click on “unlink”.
You have to keep in mind that if you are going to sell the computer, you have to do it as if it were one that leaves the factory, so you will not have to have any external device configured. Likewise, you will also have to delete the Wi-Fi networks that you have previously configured.
How to erase the hard drive
Once you have completed all the above steps, All that remains is to erase the hard drive. You have to be very clear that this step has no turning back, so you must be completely sure that you want to do it.
Steps to follow
To carry out this process you have to follow a series of steps very well
- Restart the Mac and as the screen turns on after shutdown hold down the Cmd + R keys. This will take you to the safe mode of the Mac in which a window with four options will open.
- Choose “Disk Utility”.
- Now select View > Show all devices from the menu bar.
- Select the drive you want to erase in the left column. In this case the one that contains the macOS operating system.
- Click on the “Delete” button located at the top of the window.
- You will have to fill in several fields:
- Name: type the name you want to give the disk.
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- Format: choose between “AFPS” or “Mac OS Extended (Journaled)”. It is recommended to leave the format that appears by default.
- Scheme: in case this field appears, select «GUID Partition Map».
Reinstall macOS
Once you have erased the hard drive, the computer remains as if it had just left the factory, without an operating system. You will have to reinstall the operating system. If you are going to sell the disk, it is recommended that the buyer installs it, so that they can configure it to their liking and with their iCloud accounts.
However, it is recommended that you do some tests to check that everything is fine and that you are going to sell the computer in good condition and ready for proper use. To perform this part, it is recommended that you connect your computer to a power source so that there is no risk of shutdown. In addition, you must be connected to a Wi-Fi network. When restarting the Mac, you will have to press Command + R until macOS Utilities appears, and once there you will have to click on Disk Utility. On the boot disk, you will need to remove the operating system. After this, you will have a completely clean Mac.
Things to keep in mind
Although it does not suppose much complication, you have to know that if you are going to sell your Mac, It is essential that you follow all the steps well. In this way you will not run any risk with the personal information that you may have stored on the computer. It’s easy to delete everything without leaving a trace, but you have to be clear about what you want to do, since then there is no going back.
In case you are not very sure that you can do it yourself, it is recommended that you go to a specialized center where they can help you, such as a SAT, or follow some of the advice offered on the official Apple website. In addition, in the Technical Support you have different options on restoring the Mac as well as reinstalling the operating system.
