Microwave emits sparks or arcing inside the cavity during cooking.

Safety first: Stop the microwave immediately if you see sparks. Unplug before inspecting.

User-level steps:

• 1. Remove metal objects: Ensure no metal utensils, twist ties, or foil are inside.
• 2. Clean the cavity: Thoroughly clean all walls, ceiling, and floor with a non-abrasive cleaner to remove grease and burnt food.
• 3. Inspect waveguide cover: The small mica or plastic cover on the side wall should be intact and not burnt or cracked. Replace if damaged.
• 4. Check for chipped paint: If bare metal is exposed, use a microwave-safe cavity touch-up paint to cover small chips.

If arcing continues after cleaning and replacing the waveguide cover, discontinue use and have the unit inspected professionally.