A method and structure for a non-reopening extruded plastic profile fastener wherein complementary rib and groove type profiles are constructed and arranged to be pressed into interlocking relationship, and provided with restraining means against permanent interlocking so that the fastener can be handled as an assembly with the profiles aligned for interlocking but not interlocked until the means are overridden and the profiles pressed into interlocked relation with one form of the overridable means being a frangible diaphragm across the groove to prevent movement of the rib and in another form a projecting strut which is yieldable with the application of a predetermined force or which is removable to permit the profiles to be moved to fully interlocked position.