The nanoindentation and tribological measurements were performed on DC and RF magnetron sputtered W-C coatings to optimize the deposition conditions to obtain maximum nanohardness and to compare their properties and behavior with earlier studied PECVD W-C coatings. Despite number of similarities, some consequences of a tribo-chemical transfer film formation are inconsistent with the existing wear model for W-C coatings with controlled carbon content. Transfer films in the friction contact consist from iron- and tungsten oxides and carbon generated during carbide oxidation. The role of carbon in the transfer films leading to high coefficients of friction has to be principally different from the expected lubricative role of carbon in W-C coatings and needs further study.