Abstract: An automated data storage library is disclosed for quickly switching to a second accessor when a first accessor fails. Either the first or the second accessor may be designated an active accessor and the other a standby accessor. The library includes first and second library managers, one designated an active library manager and the other a standby library manager, each of the library managers interconnected with one of the accessors for operating the interconnected accessor, and each interconnected with the other of the accessors for operating the interconnected other accessor. The active library manager may operate the first accessor as an active accessor and, upon the first accessor becoming unavailable, immediately switches to operate the second accessor as the active accessor and allows maintenance and servicing of the first accessor simultaneously with operation of the second accessor.