Reinstall Mac OS X Mountain Lion before selling a Mac
If you consider that the license for Mountain Lion doesn't look to be transferrable to the new owner (as most are probably not clear legally to transfer/sell/give away an App Store license for Mountain Lion) then other options might make more sense than just installing Mountain Lion.
Why not reinstall Lion which is tied directly to the hardware. You need no Apple ID to use Internet Recovery or the Lion recovery disk assistant. You could optionally offer to assist the buyer in upgrading to Mountain Lion and also ensure they understand iLife might not be included with this sale.
You could gift some or all of the apps to their Apple ID, give a physical gift card to cover the expected cost of the software or renegotiate the sale price of the Mac.
We have a discussion of more options on this thread:
- Where can I get a copy of Mountain Lion that I can resell with my Apple hardware?
Apple documents the reinstall and erase options at:
- https://support.apple.com/en-us/HT204904
If you happen to already have an installable copy of Lion or Mountain Lion,
- back up your personal data
- make a bootable thumb drive to install from
- boot from the thumb drive
- select Disk Utility
- repartition and reformat your drive
- there should be an arrow to skip the Apple ID entry and continue the install.
Either of the two ways should get you a virgin install.
The other way is to do a recovery boot by holding down COMMAND-R when powering on before your Mac chimes. It will be slow since all files load from Apple's servers. Follow the six steps above for a clean install.
I installed Mountain Lion on my early 2009 17" MacBook Pro via a bootable thumb drive I made.
Download and run Lion Diskmaker from http://www.macupdate.com/app/mac/39701/lion-diskmaker. This tool allows you to create a bootable thumb drive from the Mountain Lion installer. It will search your system to see if you still have the install file on hand.
If you don't still have the ML install file, check the Purchases page in the App Store. If it show Mountain Lion with a DOWNLOAD button, click the button to download Mountain Lion from the App Store but do not install it. If the app starts automatically, quit it.
Run Lion Diskmaker again and let it walk you through the process.
When you have the bootable thumb drive, make sure you have all your personal data backed up on an external drive before you use Disk Utility to repartition and reformat your laptop's hard drive and reinstall ML!
Good luck and happy selling!