Microwave is excessively loud during operation, with rattling or vibration noises.

Safety Warning: Unplug the microwave before moving or tilting it.

Steps:

• Ensure the microwave is placed on a stable, level surface. Adjust feet if provided.
• Remove the glass tray and support ring; clean and reseat them properly.
• Run the microwave briefly with a cup of water and the tray removed (if allowed by the manual) to see if the noise changes.

Technician-level:

• Remove the cabinet and check that the transformer, fan, and magnetron are securely mounted.
• Tighten any loose screws or brackets and add vibration-damping pads if specified by Insignia.

If the noise is electrical (buzzing, crackling) rather than mechanical, stop use and have the high-voltage system inspected.