Would either of these scenarios harm a microwave? 1. If you turn on the microwave with no food in it to cook? Or 2. To overcook and burn?

RICK

Burning the food will not harm the oven Running a microwave with nothing in it will as there is nothing to absorb the heat, however doing it just once should not cause damage Used to check microwaves for radiation leakage, always placed as cup of water in it to avoid damage

Rebecca

I don't know why but my mother told me never to turn on the microwave with nothing in it. I'm not sure why not. She said it can ruin it. So I never have -- and honestly why would I anyway? Sometimes if it's really dirty, I will put a soapy sponge in the microwave and start it for 30 seconds.