Abstract: A novel folding storm shutter system includes an overhead header presenting a track and a pair of laterally spaced abutment surfaces. The system includes a plurality of trolley supported shutter members which are rotatable about a vertical axis. The system further includes a sill having a guide slot which is disposed beneath the track in alignment therewith. The sill also has a pair of laterally spaced abutment surfaces. An abutment contacting element is disposed at each corner of each shutter member so that when the shutter system is deployed the contact elements come into contact with the abutment surfaces to rigidify the structure. Trolley mechanisms are provided for supporting the trolley supported shutter members from a location midway between the edges of the shutter member so that the entire assembly is evenly balanced to facilitate maneuvering and deployment of the system.