Abstract: A protective guard for ground floor windows of a dwelling or other building is disclosed herein having a barred grill or grid network releasably secured to the exterior edge marginal region of a window frame. The releasable securement includes a bolt extending through selected bars of the grill and through the window frame with a pull-out pin installed on the interior end of the bolt. A compressed, helical spring is situated between the frame and the pin for forcibly urging the release mechanism out of engagement with the bolt when the pin is withdrawn. Release of the bolt frees the grill so that the grill may be readily removed to permit passage through the window by persons or objects.