Remove the following ten screws securing the lower case to the upper case:

• Seven 3 mm Phillips screws.
• Three 13.5 mm Phillips screws.

Using both hands, lift the lower case near the vent to pop it off two clips securing it to the upper case.

Remove the lower case and set it aside.

Remove the two 5-Point Pentalobe screws along the top edge of the battery.

You do not necessarily have to follow steps 3-6 to remove the battery in order to replace the hard drive. However it is recommended to remove all power sources from electronics before working on them.

Use the tip of a spudger to bend back the finger of the "Warning: Do not remove the battery" sticker while you remove third five-point Pentalobe screw hidden underneath.

Lift the battery by its plastic pull tab and slide it away from the long edge of the upper case.

Do not try to completely remove the battery just yet.

Tilt the battery back enough to access the battery cable connector.

Pull the battery cable connector away from its socket on the logic board and remove the battery from the upper case.