Sputtered films of 1.5 μm of Mo deposited on (111) ‐oriented Si failed either by blistering or localized eruptions after various thermal treatments. Investigations were carried out to determine the amount of strain in the film associated with this unstable mechanical behavior. Two types of measurements were employed. One employs macroscopic interferometer measurements to measure deflection and the other x‐ray diffraction. A separation is made of intrinsic and thermally induced strains. The intrinsic strains are believed to be due mainly to Ar atoms embedded during sputtering which remain throughout annealing treatments. These atoms also introduce a broadening of the diffraction lines because of the special constraints associated within films. This effect is separated from the usual line broadening due to dislocations and small particle size. Annealing treatments reconfirm that dislocation mechanisms are not as effective in relieving nonuniform microstrain in films as they are in cold‐work filings of the same material.