Microwave emits a burning smell, smoke, or visible sparks (arcing) inside the cavity during use.

Immediate safety action: Press STOP, open the door if safe, and unplug the microwave immediately. Do not continue to operate the unit until the cause is identified and corrected.

User-level steps:

• 1. Remove metal objects: Take out any metal utensils, foil, twist ties, or dishes with metallic trim.
• 2. Inspect waveguide cover: Locate the small mica or plastic panel (usually on a side wall). If it is burned, cracked, or has holes, it must be replaced.
• 3. Clean thoroughly: Scrub away any burned-on food or grease, especially near the waveguide cover and ceiling, using a non-abrasive sponge and mild cleaner.
• 4. Check cavity paint: Look for chipped or flaking paint exposing bare metal. Small chips can sometimes be touched up with microwave-safe cavity paint (follow manufacturer guidance).

If arcing continues after cleaning and removing metal, or if the waveguide cover is damaged, stop using the microwave and have a technician replace the cover and inspect the waveguide and magnetron.