If the indicator remains green, it could be due to the use of an incorrect Upper-Tank filter.
The 2004 model Lift-Off Bagless vacuums were released with a taller 3" Upper-Tank filter. If you have purchased the original style Upper-Tank filter (2.5"), it will create a gap causing the Clean Filter indicator to always show green.
Please check your filter to determine if it is correct. The indicator will also remain green if the Upper-Tank filter is missing or if there is a clog obstructing the sensor.
If you need additional assistance with this, please call BISSELL Consumer Services 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.