I embarrassed to say that for ages I have had trouble with the trackpad — now on my second one. Never knew about the “magic button” until it literally fell off onto my desk. I thought about taping it back on, then had second thoughts about that solution. Found this site, and realized how important those two buttons were. Who knew? Followed the directions, using a very thin pocket knife edge to open the corner enough to let me slip in the two-part button. Connected. Used it. Fine. Thanks for great explanation and clear pictures. Then I turned the trackpad over to see my handiwork. The button was half out. It looked like the plastic panel was not fitting flush to the metal, maybe due to the corner having been lifted. Patiently repeated the process. Pressed down, still not perfectly flush. Used strong tape on sides to make it flush. Not an elegant solution but so far I have a smooth working trackpad.