There are many reasons to want to reset your computer and erase all its data by reinstalling it from scratch. Sometimes it may be that the computer has become slow and requires a complete reset after about 2-3 years of use, or if it is sold and therefore it becomes appropriate to deliver it without leaving personal data inside. private accounts or useless programs.
In this guide we see how to do a factory reset of the Mac, completely format the system and reinstall MacOS without straining too much to make it look like new.
This guide applies to all Mac models, such as Macbook, Macbook Air, MacBook Pro and iMac .
READ ALSO -> How to optimize your Mac and do MacOS maintenance
1) Back up your personal files
The first step in any factory reset of any computer is to make a backup of at least the personal data saved so far on the machine, since they can be moved very easily.
Backing up your Mac is very simple because we can use Time Machine, the system's internal cloning tool.
This tool makes a complete copy of the files and data so that afterwards you can restore them as soon as the system is restored using the same program.
To start Time Machine on your Mac, simply open the Launchpad icon at the bottom of the dock, then search for the Time Machine app among those on the system; alternatively we can find the backup program icon in the System Preferences .
If it is the first time that we use this program, we will immediately be asked to choose a destination for the backup: external hard drives, USB sticks but also network resources (Windows PC or NAS) are fine.
We click Select backup disk, choose the resource on which to save everything and start the initialization procedure in order to make it compatible with Mac.
Now there is nothing left to do but tick the item Backup automatically to start the backup; as soon as it is finished we can proceed with the system recovery. To backup immediately without waiting for the next automatic backup, we use the item Backup now present in the Time Machine icon in the top menu bar.
2) Deactivate online accounts
The second step is to disassociate all system services and permissions with your iTunes account.
To do this we will have to open the System Preferences icon, then click iCloud .
If we had already logged into the Apple account, just press Exit to disable data synchronization.
If we had added other accounts to the Mac we can deactivate them by clicking on System Preferences -> Internet Accounts .
We select the account to be deleted and use the i-shaped key (minus) on the bottom left to delete all traces of the accounts.
3) Format and reinstall the original operating system
You can install the latest version of MacOS which was downloaded from the App Store.
If you reinstall the original version of MacOS using the recovery DVD that came with the system, new owners will have the option to choose for themselves which version of the operating system to install.
To create the recovery disk we will have to follow the following steps:
- Insert the DVD into the player;
- We restart, select the language and then choose " Disk Utility " from the Utilities menu.
- In Disk Utility, select the internal hard disk and in the partition tab, give a name to the partition, set the format to " Mac OS Extended (Journaled) " and create the partition.
If you do not have a recovery disc, to reinstall MacOS on the Mac you must use the internet connection, MacOS will access Apple's servers to automatically download all the installation files.
We restart by pressing the " Command-Option-R " keys to force the Mac Restore tool to load.
After selecting the language, we choose the item Reinstall macOS to start the recovery to factory settings without using the recovery disc or the installation disc of the Mac.
Once the installation program is complete, the system restarts and the welcome screen appears.
If the computer is for sale, it is worth stopping here and shutting down the system so the new owner can set it up with his personal account.
In another article, we talked about the guide to Install MacOS from scratch from a USB stick
4) Restore backup files
On our new Mac we can restore the files that we had saved with Time Machine in two ways: from the Mac recovery tool or from the operating system.
To restore from the recovery tool, immediately press the " Command-Option-R " keys at Mac startup to force the Mac Restore tool to load.
Now we connect the external hard drive, the USB stick or any other resource used to save the backup and we use the item Restore from backup of Time Machine.
We can also use this tool with network resources, just remember the path where the backup was saved in the LAN.
If, on the other hand, we want to proceed from the operating system, we perform the entire first installation of MacOS and, once we reach the desktop, we open the Time Machine app and set the drive or network path previously associated as a resource.
Now just open any folder or file included in the backup, click on the Time Machine button at the top right and select the Enter Time Machine item .
We will immediately have access to all the backups of the folder and the files, we will only have to browse, select what to restore and finally use the Restore button.
To help you find the right backup (especially if there are many files) we can use the side arrows, the side snapshot bar and, once you find the desired file, use the space bar to preview what the file contains, so as to understand if that's what we were looking for.
