Vacuum produces a high-pitched whistling noise during use.

Safety first: Turn off and remove the battery.

• Run the vacuum briefly while listening closely (keep fingers and hair away from moving parts) to localize the whistle source.
• Inspect the dust bin, extension tube, and joints for visible cracks or gaps.
• Check that the HEPA filter cover is fully latched and that the filter is seated correctly.
• Replace any cracked components such as the dust bin or extension tube. Replace worn seals or gaskets as needed.