Just wanted to let anyone know, to make SURE to check the sensors near the bottom of the rails to ensure proper alignment. I checked these from a distance, saw each with a green light and assumed they were aligned. But when I check closely, I noticed one of the sensors had a green light, but it was slightly blinking (you wouldn't have noticed it from far away. It was off by just a hair, but enough to cause problems with the door closing. Just an FYI.