If you see an E6 error message on your Shark vacuum, it means that there is a problem with the brush roll. The brush roll might be jammed or stuck, or there could be an issue with the motor that drives the brush roll. To fix this error, turn off the vacuum and unplug it from the power source. Remove any debris or tangled hair from the brush roll and clean the motorized floor nozzle. If the problem persists, contact Shark customer service for further assistance.