Microwave makes loud rattling, vibrating, or metallic noises during operation, even with normal heating.

Safety: Stop the microwave and unplug it before inspecting the interior.

Steps:

• Check for metal: Ensure there is no metal cookware, foil, twist ties, or utensils inside. Remove any such items immediately.
• Inspect waveguide cover: Look at the small mica or plastic cover on the side wall (waveguide cover). If it is loose, warped, or burned, discontinue use and have it replaced.
• Check turntable components: Ensure the glass tray and roller ring are properly seated and not contacting the cavity walls.
• External vibration: Make sure the microwave is on a stable, level surface and not touching adjacent cabinets or walls that can amplify vibration.

If noise persists and seems to come from inside the cabinet (fan or transformer area), have a technician inspect for loose components or failing fan motor.