If the Filter Indicator remains red, this could indicate that airflow is reduced or clogged by a dirty filter. - Check the Upper Tank area and the Pre and Post-Motor filters for debris. Dirty filters can restrict airflow. The pre-motor foam filter is square and located in a pull out tray underneath the dirt cup. The Multi-Layer Post Motor Filter is rectangular and located on the side of the machine. The foam filter may be hand washed in cold water with mild detergent. Reinstall the filter when it is completely dry. Note: The white Multi-Layer Post Motor Filter is not washable. If you continue to experience difficulty, please call Consumer Care at 1-800-263-2535, Monday - Friday 8 a.m. to 10 p.m., or Saturday 9 a.m. to 8 p.m., ET. A representative will assist you.