I had the same problem. Microwave motor starting buzzing when I close the door and F6 error on my Kitchenaid over stove. I unplugged it overnight but it still did not work. I read about slamming the door, which I did several times, (cheaper than making a service call). It eventually worked. No news on how long this will last but keeping fingers crossed. Adding sledge hammer back to my appliance repair bag, just in case I encounter a similar problem in the future.