DIAGNOSIS: This is manufacturing residue. Protective oils or packing materials on the heating element or interior metal are burning off.
FIX: Run the air fryer empty at maximum temperature (400°F) for 20-30 minutes in a well-ventilated area or outside. The smell should dissipate completely after one or two cycles. This is a required break-in procedure often omitted from quick-start guides.
IF THAT DIDN'T WORK: Check for non-food foreign objects. Remove the basket and pan and inspect the heating element chamber for stray plastic packaging, labels, or foam.
HEADS UP: If the smell is acrid and continuous, or you see sparks, unplug immediately. A wire insulation may be contacting the heater. This is a fire hazard. Do not use.