How to Prepare a Used Mac for Sale


If you’re planning on buying a new machine, it’s a great idea to sell your old Mac to cover some of the new computer’s cost. I’m currently going through the process of preparing my machine to replace it with a new MacBook Pro, so follow along with me as I make sure the process is as painless as possible for both me and my Mac’s next owner.

Back Up Your Content

What would you do if you sat down at your new computer one day and realized a desperately important file was still on your old hard drive? In order to prevent from happening, you should make a backup of at least your most important files. If you have an external hard drive, that makes it easy, but if you’re only copying text documents or small numbers of photos, even a USB flash drive might be enough. I’d suggest at least making copies of your Documents and Photos folders, since they’re the folders most likely to contain important files.

Or, if you’re not sure what you should keep, go whole hog and backup your entire hard drive. You can do this with a utility such as Carbon Copy Cloner, which copies a drive’s contents to another volume to keep them safe. It’s a good idea to make sure you have a large capacity external drive if you’re doing this: one that has more than enough room for your files.

Deactivate or Deauthorize Software

Some applications, such as iTunes and Adobe products, require each of your computers to be authorized to use them. Before you wipe your data, make sure to deactivate any applications that need activating so they can run on your new machine. With iTunes, you can deauthorize a computer by going to Store > Deauthorize Computer. Adobe’s applications can be deactivated by going to Help > Deactivate. Deauthorizing iTunes isn’t as important as it is with Adobe’s applications, since you can deauthorize after the fact through your iTunes account.

Destroy Everything

Once you’re certain you have a backup of everything you could possibly ever need again, you’re going to want to erase your entire hard drive to ensure there’s nothing personal left on there. To do this, you’ll want to find the OS X install disc that came with your machine. Insert the DVD into your drive, and restart the computer holding down the C key. Instead of loading OS X from your machine, the Installer will load from the disc. Once it does, choose Disk Utility from the Utilities menu. From there, you’ll be able to select your hard drive and erase it. In order to make sure there’s no way anyone could restore any of your personal data, I’d choose Security Options and select either Zero Out Data, or if you have more time and want to be extra sure there’s nothing left, 7-Pass Erase. Everything on the drive will be overwritten, so there’s a very small chance anything could be recovered.

Of course, if you don’t want to risk even using the security options, you could always spent a small amount of money on a new hard drive and destroy the old one completely. A large hammer will do the trick, and I’m not even joking. There’s no way anyone’s getting your data back from a hard drive that’s in pieces.

Reinstall OS X

While the OS X install disc is still in your machine, now is a good time to reinstall the operating system. Simply run the installer from the disc. When your Mac reboots, make sure you don’t start running the Setup Assistant. The new owner of your computer will be happier to set it up as if it were a brand new Mac than have to run from the setup you set up. Once the Setup Assistant appears, just hit Command-Q to quit and eject the disc. When the Mac is next turned on, the Assistant will run and the new user can set it up however he/she wants.

Give It a Cleaning

No one wants to open a box to find a grubby computer covered in fingerprints and old bits of food. So give your Mac a good cleaning using a soft, damp cloth (when it’s turned off, of course). If it’s a laptop you’re selling, you could also — carefully — turn it upside-down and shake out some of the crumbs in the keyboard and in the hinge. Use a different cloth to wipe away smears and fingerprints from the screen (a microfiber or glasses cloth works well).


Once you’ve done all of the above, your Mac is ready to be passed on to another user who will hopefully take good care of it. Did I miss any vital steps? Let me know in the comments.

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