A door system including, a door movable between a closed vertical position and an open horizontal position, a cable attached to the door and normally providing a counterbalancing force to the door, the cable extending along a vertical line adjacent the door and being normally substantially taut, and an anti-drop assembly having a pawl pivotally supported on the door and attached to the cable, a stop surface positioned adjacent to the door, and a spring operable to urge the pawl toward engagement with the stop surface, wherein when taut the cable opposes the biasing force of the spring and wherein upon the cable going slack the spring urges the pawl into engagement with the stop surface to decelerate the door.