After you change your filters, you have to hold down the night mode button on the remote control for 5 seconds. The onboard screen will show a countdown. I don't know why this is not in their article. And I don't know why these brilliant Engineers can't answer a simple question. But if you have changed the filters on your air purifier and the filter warning on the onboard screen is still showing, click the Moon shaped icon button on your remote control and hold it for 5 seconds. It will fix the problem. This is the real answer.