A fastening tool comprising: a housing having an engine receiving portion; a drive engine located in the engine receiving portion, the drive engine comprising a cylinder and a piston reciprocally mounted within the cylinder, the piston comprising a driver configured to move along a drive axis to drive a fastener during a drive stroke; a nose assembly carried by the housing, the nose assembly comprising a fastener drive track configured to receive the driver, and a movable portion biased in a retracted position towards the housing and movable to an extended position away from the housing; a magazine assembly constructed and arranged to feed successively leading fasteners from a supply of fasteners contained therein into the drive track; and an actuation device configured to actuate the drive engine to initiate the drive stroke, the actuation device comprising a contact trip assembly operatively connected to the movable portion of the nose assembly, the contact trip assembly comprising a lower contact arm connected to the movable portion of the nose assembly biased in the retracted position and movable to the extended position with the moveable portion of the nose assembly, and an upper contact arm operatively connected to the lower contact arm; and a trigger assembly comprising a trigger, and a trigger arm pivotally supported by the trigger and configured to interact with the upper contact arm, wherein the fastening tool is characterized in that the trigger assembly further comprises a check pawl configured to engage an opening in the upper contact arm when the upper contact arm moves downward to prevent the tool from being operated in a contact trip mode. a housing having an engine receiving portion; a drive engine located in the engine receiving portion, the drive engine comprising a cylinder and a piston reciprocally mounted within the cylinder, the piston comprising a driver configured to move along a drive axis to drive a fastener during a drive stroke; a nose assembly carried by the housing, the nose assembly comprising a fastener drive track configured to receive the driver, and a movable portion biased in a retracted position towards the housing and movable to an extended position away from the housing; a magazine assembly constructed and arranged to feed successively leading fasteners from a supply of fasteners contained therein into the drive track; and an actuation device configured to actuate the drive engine to initiate the drive stroke, the actuation device comprising a contact trip assembly operatively connected to the movable portion of the nose assembly, the contact trip assembly comprising a lower contact arm connected to the movable portion of the nose assembly biased in the retracted position and movable to the extended position with the moveable portion of the nose assembly, and an upper contact arm operatively connected to the lower contact arm; and a trigger assembly comprising a trigger, and a trigger arm pivotally supported by the trigger and configured to interact with the upper contact arm, wherein the fastening tool is characterized in that the trigger assembly further comprises a check pawl configured to engage an opening in the upper contact arm when the upper contact arm moves downward to prevent the tool from being operated in a contact trip mode.