in this paper, we discuss the mechanism of detachment of thin pre-stressed films from a flat smooth rigid substrate. Indeed, we develop an analytical solution in closed form which shows how the critical value of the pull-off force strongly depends on the press-stress P-0. In detail, the critical pull-off force needed to detachment is shown to be higher for prestressed tapes. Furthermore, we notice that; when a high prestress is present, tapes may behave in different manner and spontaneously detach from the rigid substrate.