Usability is typically conceived of as a property of a software artifact (“a software product has good/bad usability”) and tested in user experiments. In this conceptual paper we challenge this established view. For doing so, we draw on the concept of sociomateriality and a case study, which illustrates how usability of a workplace telephony software is perceived and treated very differently in usage practices across use contexts. We find that the software interacts with different types of hardware and with institutionalized ideas and norms in the various contexts of user organizations in such a way that it renders defining usability as a property of the software artifact a pointless task. In fact, we question whether it is useful to conceptualize (workplace) software as artifacts with stable set of properties. Rather, we argue that usability manifests in the sociomaterial use context. We discuss methodological implications and identify areas for future research.