I had the same problem. The plastic post that holds the cam that pushes up on the door latch had sheared off. Really not a good design considering the repetitive force on that post. Luckily, the post is hollow! Once you have access to the inside of the microwave, it's likely that you will see the cam and the sheared-off post sitting on the bottom of the unit. You will see a small circular impression on the black plastic board that has the switches on it-- next to the very bottom switch. You can drill a small hole in the center of this depression and put a small machine bolt through, with a washer and nut on the other side, and then push the cam back on the post. The cam locks on a small tab next to the reattached post. Total cost of parts for this repair was $0.70 for me at my local Ace hardware. You'll find the right parts in the small specialty screw and fastener bins. I hope this helps.