A surgical stapling apparatus (stapler) is provided and is configured tocouple to a reload.The reload includes a first jaw member releasably supporting a cartridge thatincludes a slidedeflector that is movable from a first position to a second position. One ormore lockout stepsare provided on one of the first and second jaw members of the reload. A drivemember includesa working end urged to move toward the lockout step. In the first position,the slide deflector ispositioned to prevent engagement of the working end of the drive member withthe lockout step,and in the second position the slide deflector is positioned to allowengagement of the workingend with the lockout step to prevent further advancement of the working end.Distal translationof the working end causes the slide deflector to move from the first positionto the secondposition.
