Locking, performance zipper stays closed when it should. To unlock and open the zipper, ensure that the zipper pull tab is directly perpendicular (i.e. 90°) to the track. The zipper pull and track should form an upside down "T" shape when unlocked and will pull smoothly when opened. When the zipper pull tab is laying flat, or has been opened beyond 90°, the zipper is in the locked position. Forcing the zipper open in the locked position will result in difficulty in pulling and damage to the zipper. Contact us for any issues