Why is my microwave making sparks inside?

Sparking inside a microwave can mean unsuitable cookware, metal trim, food splashes or a more serious internal issue. Stop the appliance immediately if you see sparks, flashing or hear snapping, then let it cool before checking anything else.

1. Unplug the microwave and remove all cookware, foil, twist ties and metallic packaging. Expected result: the cavity should be free of anything that can arc.
2. Inspect the inside walls, ceiling and turntable area for dried food or grease. Clean stubborn splashes with a soft damp cloth once the oven is cool. Expected result: the cavity should be clean and dry before the next use.
3. Check that all dishes are marked microwave-safe and have no metallic decoration. Expected result: only suitable cookware should go back into the oven.
4. Run a very short test with a microwave-safe bowl of water. Expected result: there should be no sparks, crackling or burning smell.
5. If sparking happens again, stop using the microwave and contact the retailer or store where it was purchased.

Never use a microwave that sparks repeatedly. Do not scrape coatings, open the housing or continue testing it if there is any smell of burning.