Systems for preventive care seek to provide healthcare services to citizens at risk of developing disease. In doing so they wrestle with identifying the citizens at risk of developing lifestyle-related disease and with reshaping the existing healthcare infrastructure into effective health offers for these citizens. In this study we analyze how a system for preventive care was enacted through a pilot implementation. The temporariness of the pilot implementation was, we argue, central to its contribution toward bootstrapping the system. By being temporary the pilot implementation became a means of acquiring clinical evidence for the cost-effectiveness of the system prior to committing to its long-term and large-scale use. The temporariness also legitimized temporary solutions to issues that otherwise made it difficult to bring actors, practices, and technologies into alignment. Once aligned, even if merely temporarily, the resurfacing of these issues after the pilot implementation will be shaped by the experiences from the pilot implementation. In this way pilot implementations have a generative role in infrastructure evolution; they are not merely tests but help bootstrap systems by making alignment manifest and benefits salient. We discuss this generative side of learning in pilot implementations and the extent to which they can enact a system by bootstrapping it.