Diagnosis
A foreign object is likely caught in the fan blades, or a filter is not seated correctly, causing vibration.
How to Fix It
Power off and unplug the unit. Remove both the front cover and the top cover. Inspect the interior fan chamber for debris like paper or plastic. Remove any obstructions. Reseat both the Max2 and Green True HEPA filters, ensuring they click fully into place. Reassemble the covers securely.
If That Didn't Work
The noise may be a bearing issue in the main blower fan. Listen closely. If the buzz or grind is centralized behind the filter compartment, the fan motor assembly may require service. Contact Coway support for a diagnostic.
Heads Up
Do not operate the unit with a persistent rattling noise. It can indicate a loose component that may damage the fan or motor. Always unplug the purifier before inspecting the interior.