Reset a MacBook by backing up your personal files, deauthorzing any cloud services and restarting your Mac in Recovery Mode. Next, erase the hard drive, and reinstall OS X to complete the reset. Be sure to connect your MacBook to a power adapter, as this process may take several hours.Continue Reading
If you wish to keep your settings and information intact, Macworld recommends cloning your internal hard drive to an external drive. You may do this with apps like SuperDuper or Carbon Copy Cloner. This allows you to access all your old files and gives you the option to restore your MacBook.
Remove your information from all apps that are locked to your Mac, including iTunes, iCloud and Photoshop and other third party applications.
Restart your Mac. While it boots up, hold down Command and the R key to access Recovery Mode.
Click on Disk Utility, and select Continue. Next, click Unmount followed by Erase. Exit the Disk Utility, and access the OS X Recovery or Internet Recovery option. Select Reinstall OS X. In order to properly reinstall, you must be connected to the Internet. Finally, restart the MacBook.