How to restore Mac to factory settings / how to sell on your Mac

I did a google for “How to restore Mac to factory settings” and all the hits back seemed to be talking about deleting everything manually and then restoring the operating system from a disk! There is a much better way; I’m assuming your intention to restore to factory settings is because you want to sell on or pass on your Mac to someone? Follow these simple steps and you will effectively do what the title suggests.

1. Make sure you have a full back up of all your files, and you have transferred them to a new Mac and it is working and you have verified all your files have been copied.
2. De-authorise your computer in iTunes on the Mac you are getting rid of
3. You should have already disabled Time Machine on the Mac you are getting rid of, as part of the transfer to the new Mac.
4. Now create a user account with admin privileges for the person you are passing the Mac onto, if you don’t know who this is going to be make it something generic like “Administrator” - the most important thing is that you give them full admin privileges that you current account has.
5. Check that you can log in to the new account, and that it has admin rights. This can be done by unlocking a setting in System Preferences where it will ask you for your admin password.
6. Make the hard drive appear on the desktop by going to finder > Preferences > and choose “Show hard drives” on desktop.
7. Change the hard drive name to take our your name; right click on the hard drive > get info > update the name.
8. Change the name of the computer to take our your name. Go to System Preferences > Sharing > the change the computer name.
9. Now under System Preferences > User & Groups, unlock for changes and then choose the user account you want to remove and click the minus sign. It may take up to 10-15 minutes to process (giving a bouncing ball and even saying “unresponsive” in system monitor - however it will come back).
10. Once you get to the next screen you will be able to choose to delete the home folder of this user and its contents and choose “delete securely”, then click ok/apply.
11. Leave the computer to delete the account - this may take up to 12+ hours depending on the size of the user account (for me it took this long for 200GB+ user account). You can monitor progress by doing a get info on the hard drive and watching the available disk space increase over time.
12. Once deleted there should now be lots of spare space.
13. The remaining steps are manual, if you have any files stored outside the home directory then these need to be deleted. Apps do not get deleted, so these too will need to be manually deleted if you don’t want them transferred to the new user.

And that in a nut shell is it - you’ll then be giving the new owner basically a brand new laptop reverted to factory settings.