When it finishes, shut down the computer.If a prompt for an Apple ID appears, return to Step 5. Select Install Mac OS X from the Utilities menu.The fastest method is sufficient since all but the most expensive techniques and equipment will be able to recover securely erased data.The more 'securely' you erase the disk, the longer it will take.Select the 'Security Options' button and erase the disk.Select the Mac's hard disk icon, then select the 'Erase' tab.Remove any partitions you may have created.Select Disk Utility from the Utilities menu.

Remove any Open Firmware password if you created one: select Firmware Password Utility from the Utilities menu and remove it.

This method forces the Mac to download its originally installed OS from Apple's servers, which will not require an Apple ID to install.

Keep the other three fingers where they are until you see the 'spinning globe' icon.

With a fourth finger press the power button to turn on the Mac.

using three fingers press and hold the following keys: ⌘ (command), option, and R.If your Mac did not ship with discs, boot OS X Internet Recovery:.If your Mac shipped with a grey System Install DVD, start your Mac with that disc inserted in the optical drive while holding the c key to boot from it instead of its internal volume, which should be erased before selling it.Next: Remove all your personal information by completely erasing the Mac's internal storage. Select 'Delete from Mac' when it appears. System Preferences > iCloud > de-select 'Back to My Mac' and 'Find my Mac'.If you enabled FileVault, disable it in System Preferences > Security & Privacy.Refer to What to do before selling or giving away your Mac To correctly sell or transfer ownership of a Mac, even to someone in your family, you must follow these instructions. To properly transfer ownership you must do what the former owner should have done before parting with it.

How to reset apple macbook pro 2011