Abstract: An auto-arresting safety device, comprising a housing; a fall arrest system supported by the housing, and having a first component moveable with respect to a second component, the fall arrest system being actuatable in response to a load to arrest movement of the first component relative to the second component, the fall arrest system being resettable to restore movement of the first component relative to the second component upon the load being at least partially removed; and a disabling system operable to prevent resetting of the fall arrest system upon the load exceeding a threshold load, such that, when actuated, the disabling system renders the safety device inoperable.