Experiments show that the onset of electrical conductivity in cold deposited films of some metals (Pb, Hg and Ga) is strongly dependent on the substrate material. Thus, in films on glass substrates the thickness of the conductivity onset dco is more than 20 atomic layers, at the same time, in films deposited onto predeposited layer of SiO or Ge dco is about 10 times smaller. Our experiments show that high thickness values of the conductivity onset are due to formation of metastable insulating modifications of these metals. We propose also the model of the insulating state. In this model the film consists predominantly of diatomic metallic molecules.