There are a few reasons that could cause a loud noise with your grinder. First, ensure that after a grind that the amount of ground coffee in the filter is correct and not too low. Make sure the beans container is empty and ensure that the grinder funnel is clean and not clogged with coffee ground. If this is the reason use the cleaning brush to unclogged the grinder funnel as described in the manual. Check that you have correctly cleaned and inserted the upper burr properly into the grinder as described in the manual. Add beans back into the container and make another grind delivery to ensure the noise has stopped.