Stephen Mumford and Rani Lill Anjum have argued that a theory of free will that appeals to a powers-based ontology is incompatible with causal determinism. This is a surprising conclusion since much recent work on the intersection of the metaphysics of powers and free will has consisted of attempts to defend compatibilism by appealing to a powers-based ontology. In response I show that their argument turns on an equivocation of `all events are necessitated'