Q: how do I prepare my MacBook air for sale

I believe this is how you do it:

Boot the Mac you are going to sell into recovery mode.  Do that by (re)starting the Mac while holding both the Command and "R" keys until after you see the Apple logo.

One of the choices you will see there is Disk Utility.  I believe you can erase your disk from there.  I believe you can also select a security option (e.g., overwrite with zeroes seven times) if you wish.

Create a new Admin account on the machine and delete the other ones.

If a SSD, then create a small file and use the Finder to duplicate it until Acivity Monitor shows a nearly full boot drive (minus other partitions you've created like BootCamp, delete those also first). Once that's completed trash and empty trash all those duplicated files, then duplicate the process again with another small file, filling the drive near full again. It's not government approved secure erase, but hopefully should overwrite your personal files.

Secure erase data on a Solid State Drive?

If it's a hard drive, then use Disk Utility to zero or 3x-7x secure erase the FREE space on your drive.

Technically the machine is still yours since you didn't restore the previous OS X version by erasing the drive, the next owner could have problems updating OS X or may do criminal behavior then the cops are at your door.

For more complete, do the reset here combined with the secure erase methods.

Reset your Mac

Follow these instructions step by step to prepare a Mac for sale:

Step One - Back up your data:

       A. If you have any Virtual PCs shut them down. They cannot be in their "fast saved" state. They must be shut down from inside Windows.

       B. Clone to an external drive using using Carbon Copy Cloner.

          1. Open Carbon Copy Cloner.

          2. Select the Source volume from the Select a source drop down menu on the left side.

          3. Select the Destination volume from the Select a destination drop down menu on the right

              side.

          4. Click on the Clone button. If you are prompted about creating a clone of the Recovery HD be

              sure to opt for that.

               Destination means a freshly erased external backup drive. Source means the internal

               startup drive.

Step Two - Prepare the machine for the new buyer:

          1. De-authorize the computer in iTunes! De-authorize both iTunes and Audible accounts.

          2, Remove any Open Firmware passwords or Firmware passwords.

          3. Turn the brightness full up and volume nearly so.

          4. Turn off File Vault, if enabled.

          5. Disable iCloud, if enabled: See.What to do with iCloud before selling your computer

Step Three - Install a fresh OS:

     A. Snow Leopard and earlier versions of OS X

          1. Insert the original OS X install CD/DVD that came with your computer.

          2. Restart the computer while holding down the C key to boot from the CD/DVD.

          3. Select Disk Utility from the Utilities menu; repartition and reformat the internal hard drive.

              Optionally, click on the Security button and set the Zero Data option to one-pass.

          4. Install OS X.

          5. Upon completion DO NOT restart the computer.

          6. Shutdown the computer.

     B. Lion and Mountain Lion (if pre-installed on the computer at purchase*)

         Note: You will need an active Internet connection. I suggest using Ethernet if possible because

                   it is three times faster than wireless.

          1. Restart the computer while holding down the COMMAND and R keys until the Mac OS X

              Utilities window appears.

          2. Select Disk Utility from the Mac OS X Utilities window and click on the Continue button.

          3. After DU loads select your startup volume (usually Macintosh HD) from the left side list. Click

              on the Erase tab in the DU main window.

          4. Set the format type to Mac OS Extended (Journaled.) Optionally, click on the Security button

              and set the Zero Data option to one-pass.

          5. Click on the Erase button and wait until the process has completed.

          6. Quit DU and return to the Mac OS X Utilities window.

          7. Select Reinstall Lion/Mountain Lion and click on the Install button.

          8. Upon completion shutdown the computer.

*If your computer came with Lion or Mountain Lion pre-installed then you are entitled to transfer your license once. If you purchased Lion or Mountain Lion from the App Store then you cannot transfer your license to another party. In the case of the latter you should install the original version of OS X that came with your computer. You need to repartition the hard drive as well as reformat it; this will assure that the Recovery HD partition is removed. See Step Three above. You may verify these requirements by reviewing your OS X Software License.

And, that's all covered if you read through it carefully.

You need to return the computer to a blank state to be sure nothing of yours is accessible. Reformat the drive and use a Zero Data erase - single pass. Do not reinstall the OS.

zainman88 wrote:

 

will erasing the disk also remove the operating system?

Yes, turning over ownership requires the entire drive erased.

Secure erased is a longer step of course as you have to overwrite the deleted data as well.

will it boot back into OS X Mavericks?

It will boot to a flashing folder with a question mark on it with no bootable OS X.

I don't want to download the 5GB update again!

Find a faster Internet connection or take it to a local PC/Mac person with one.

Obviously the next owner will want to check it out, can't do that with no OS X on it.