Point-Surface-Origin@ PSO@ macropitting occurs at sites of Geometric Stress Concentration@ GSC@ such as discontinuities in the gear tooth profile caused by micropitting@ cusps at the intersection of the involute profile and the trochoidal root fillet@ and at edges of prior tooth damage such as tip-to-root interference. When the profile modifications in the form of tip relief@ root relief@ or both are inadequate to compensate for deflection of the gear mesh@ tip-to-root interference occurs. The interference can occur at either end of the path of contact@ but the damage is usually more severe near the start-of-active-profile@ SAP@ of the driving gear. An FZG-C gearset (with no profile modifications) was tested at load stage 9 and three pinion teeth failed by PSO macropitting. It is shown that the root cause of the PSO macropitting was GSC created by tip-to-root interference.