Abstract: A motor driven roller shutter (10) employs a curtain (11) having a leading edge (12) and being adapted to slide vertical in a guide channel (14) between a raised position and a lowered position. A locking assembly (13) is secured to the channel (14) and is engageable with the shutter adjacent the leading edge (12) to inhibit the leading edge being levered away from the lowered position. The leading edge includes a flange (15) d the locking assembly includes a retractable foot (16) extending from a housing (17) so that in order to raise the shutter (11), the foot (16) must be retracted into the housing (17). A solenoid inner circuit is used to retract the foot (16) which then engages a limit switch to make the circuit to a motor to raise the curtain. Typically, the two locking assemblies are used opposite ends of the leading edge of the curtain.