The IT landscape in German hospitals is characterized by great heterogeneity. While IT-systems directly supporting medical diagnosis generally show high adoption rates, acceptance of process supporting systems, such as systems supporting the documentation processes, is often not as originally envisioned when the system was implemented. This research analyzes physicians’ perceptions towards adopting a digital archive system, which is currently not used as originally intended by the IT-department. Based on the Unified Theory of Acceptance and Use of Technology (UTAUT) extended with findings of an extensive review of the literature a research model is develop and tested with an in-depth case study at a large teaching hospital in Germany. The findings identify effort-related outcome expectations amongst the most relevant factors for physicians’ IT adoption behaviour. This contrasts prior research where -if at all- weak impact of effort expectancy on physicians’ behavioural intention has been identified. Further findings show that, although physicians report high computer self-efficacy, training is absolutely crucial to facilitate system usage, as study objects were frequently unaware of the systems’ capabilities.