First of all, try to get the robot vac to automatically empty into the docking station. If you can hear that it is blocked, or if the lights are flashing or a verbal warning sounds about a blockage, repeat the steps required above. It is usually an item becoming trapped or tangled in the roller. In messy emergencies you may need a more intensive clean, for which items like q-tips or cotton buds can prove invaluable for cleaning all of the tiny details of the robot vacuum. Good luck!