Microwave makes a rattling or vibrating noise during operation, especially at high power.

Steps:

• Remove any items from the top of the microwave.
• Ensure the microwave is on a flat, stable surface with all feet touching.
• While the unit is running (with a safe load inside), gently press on different areas of the cabinet (top, sides) to see if the noise changes; this can identify loose panels.
• Unplug the unit and tighten any accessible external screws on the cabinet.

If the noise persists and seems to come from inside, an internal component such as the fan or transformer mount may be loose. Internal tightening should be done by a technician.