This microwave was just installed today (6/30/2021) and when i turned it on it has an unusual  loud humming noise.  I immediately called the retailer i purchased it from and they said it will take a couple days for an LG certified repairman to get in touch with me for an appointment.  EXTREMELY disappointed!  I've never had issues with LG products. The fact that the microwave is brand new and is now installed with an issue infuriates me.