A surgical stapling apparatus, comprising: a first jaw member； a second jaw member； a cartridge (412) configured to be selectively coupled to the first jaw member, the cartridge including a plurality of fasteners and defining a knife channel (414) and an aperture； a drive member translatable from a retracted position to an advanced position to drive the plurality of fasteners from the cartridge toward the second jaw member； an actuator (432) rotatably supported on the cartridge and having a tip (451a), the actuator having a first position in which the tip extends into the channel and a second position in which the tip is positioned outside of the channel； and an interlock (450) having a nonblocking configuration and a blocking configuration, the interlock being configured to prevent translation of the drive member from the retracted position towards the advanced position in the blocking configuration, wherein the interlock rotates to the blocking configuration in response to the actuator rotating to the second position.
