When an Enterprise Resource Planning (ERP) system is unable to adapt in a satisfactory way to the environment or the circumstances around a specific organization we have a ”misfit”. In the ERP literature misfits is very often reported although there seems to be a lack of common understanding of what constitutes misfits and how to investigate misfits throughout the lifecycle of an ERP system. In this paper, I compare a case study from a major engineering company with the most comprehensive categorization framework of ERP misfits. Never the less my coding of qualitative interview data reveals that misfit in the case goes beyond what the framework prognosticates. In the concrete, I then develop an extended model of sources of misfit for ERP adoption in large organizations and a new categorization of the nature of misfits. The empirical material also shows that depending on the socio-technical design, the ERP-systems attributes may or may not cause a notion of misfit. This implies that in the investigation of sources and nature of misfits it is necessary to focus more on how the system is constraining the socio-technical design, and how a better socio-technical design can be achieved.