Open the cabinet that houses the electrical outlet from which the microwave receives power, and then unplug the microwave's power cord.
Locate the screws that go through the floor of the cabinet directly above the microwave and remove them, using a screwdriver.
Remove the microwave from the mounting bracket that connects to the back of the wall. This process will differ slightly, depending on the make and model of microwave you have. In most cases, you must lift up slightly on the microwave to lift it off the retaining lip. Discard the old microwave.
Remove the screws that secure the old bracket to the wall if you plan to install a different make or model of microwave. Discard the old bracket. Place the new bracket against the wall in a level position and secure the bracket to the wall with the supplied screws. Make sure the screws go into the stud work behind the walls. Otherwise, you must use toggle bolts to secure the bracket. If you are replacing the microwave with the same make and model, you can forgo this step.
Feed the electrical cable of the microwave into the hole in the cabinet where the electrical outlet is located as you lift the microwave and place it on its mounting bracket.
Secure the microwave to the top cabinet, using the supplied screws and a screwdriver.
Plug the new microwave into the electrical outlet.
Things You Will Need
- Some under-cabinet microwaves are designed to be connected to a vent system. Follow the manufacturer's instructions for attaching a hood exhaust duct to your particular model if the microwave needs to be vented outside.