Feel like you need a clean slate? Whenever you want to, you can restore the factory settings on your Mac. This means erasing all your data, everything you’ve done on the computer, and reverting it back to just like it was when you took it out of the box (well, probably with a few more dings and scratches, depending on the age).
Ordinarily, losing absolutely everything unique on your Mac would be cause for concern, and possibly thrown keyboards. But there are scenarios where a full wipe and restore session can prove valuable. The most common is when you want to sell your computer as a used device through someplace like eBay or Craigslist. No buyer is going to want a computer with a hard drive full of someone else’s data, so resellers typically work to reset the computer.
Part of this includes de-authorizing the computer in iTunes, removing any personalized login information, removing firmware passwords, and generally cutting off all connections to the cloud. But another important part is restoring factory settings. So if you are planning on selling or gifting your Mac to someone else, go the extra mile and take the time (really not much time at all) to wipe it first.
Factory settings: Erase your Mac
Now, go to the Apple menu (the one that has the Apple logo on it) and select the Restart option. Wait patiently for your Mac to shut down and then begin the startup procedure. During the restart process, before moving onto the login screen, your computer will show a gray slate screen. This is your opportunity to go behind the scenes: Hold down both the Command key and the R key when you see gray.
This should pop you over to the MacOS Utilities, where you can make various important and potentially dangerous changes. Select Disk Utility. Now, this process is going to be a little different based on what version of MacOS you are using, but you will want to look for your startup disk or other startup-related information. Select it and then click on the Erase tab. Next, head over to the Format option and set it to Mac OS Extended (Journaled). Again select Erase. This may take some time. Once finished, go to the Disk Utility menu and select Quit Disk Utility.