The flow sensor and feeder are sensitive tools. As Ultimaker we work hard to make them reliable and we are monitoring this thread to see where we can improve upon.   Just a few reminders: - Check the pressure setting of the filament feeder. On the side of the feeder is a gauge which should sit in the middle of the scale. It might be a production error when this feeder was not tigthened. When the feeder wheel is slipping you can increase pressure here. - Ultimaker tested with