Vacuum makes a loud high-pitched whine during operation.

Safety first: Remove the battery before inspection.

• Check for air leaks: Run the vacuum briefly and listen around the dustbin and joints for whistling. Ensure all parts are fully seated and latches closed.
• Inspect dustbin and cyclone: Look for cracks or gaps that could cause high-pitched air leaks.
• Clean fan path (if accessible): Some models allow limited access to the fan area; remove any visible debris.
• If noise comes from motor area and persists: The motor bearings are likely worn. Continued use can lead to failure; have the motor assembly replaced by a technician.