Microwave emits a burning smell, smoke, or visible sparks inside the cavity during cooking.

Safety first: Immediately stop the microwave and unplug it if you see sparks or smoke. Do not open the door until arcing stops, then carefully open to ventilate.

Step-by-step checks:

• 1. Remove metal objects: Ensure no metal utensils, foil, or twist ties are in the cavity.
• 2. Clean thoroughly: Once cool, clean the interior walls, ceiling, and floor with a mild detergent to remove grease and carbonized food.
• 3. Inspect waveguide cover: Check the small mica or plastic cover on the side wall (waveguide cover) for burns, holes, or charring. Replace if damaged.
• 4. Check cavity paint: Look for chipped paint exposing bare metal. Touch up with microwave-safe cavity paint if minor; if severe, consult a technician.