New materials for wear and corrosion protection are being explored in the family of high entropy alloys. However, there is limited work on wear-corrosion synergies of these alloys, particularly for magnetron sputtered thin films, where nanoscale morphology and defects strongly affect the performance and often yield different behaviors than for bulk counterparts. In this work, CoCrFeMnNi is tested as a protective thin film under non-ideal conditions. Wear-corrosion synergies are explored for films with and without low nanometer-scale voids. The influence of corrosion on wear is tested by microtribology on pre-corroded samples, while the influence of voids and wear on corrosion is tested by electrochemical tests of pre-worn and non-worn samples during optical microscopy in 3.5% NaCl solution. 1–10 nm wide intercolumnar voids cause the formation of a millimeter-scale zone of accelerated dissolution inside the film, which propagates between columns. Anodic polarization causes an electrochemically driven delamination of the coatings. Pre-scratching of the films does not alter this corrosion mechanism significantly, except for preferential initiation of delamination at the wear track. After corrosion, the wear rate is increased by up to 320% for voided films and decreased by up to 50% for the dense films. This work provides a more realistic view of the strength and limitation of magnetron sputtered high entropy alloys as protective coatings.