Metallic magnetic multilayers with very thin discontinuous magnetic layers are considered. Existence of the windows (strips) in magnetic layers leads to the additional scattering mechanism for the electrons in non-magnetic spacer. Transition from antiparallel to parallel ordering of magnetic moments in nearest magnetic layers versus external magnetic field causes the change of boundary condition for the wave function of electrons in the spacer. It has to increase the magnetoresistance in such structures as compared to the multilayers without windows.