You need to loosen the chain at the trolley so that you can remove it from the sprocket on top of the motor housing. Once this is done, plug the unit in and run the motor (without attaching the chain) until that sprocket goes counter-clockwise and stops. The opener is now in the door open position. Re-install the chain with the door in the up position and re-tighten. Give it a try! I took this recommendation from a post on Welcome to That Home Site and will try on mine later on since I also have the same problem. Good Luck!