Extant theory suggests that paths of development, although identified as being unsustainable, might be difficult to depart from. The aim of this study has therefore been to explore and understand how a path change can be facilitated in a setting of complex product systems. A unique single case of product development that managed to curb an unsustainable intergenerational cost escalation for complex defence equipment has been studied. The study shows a relation between a path change and a challenging opportunity, and also indicates how this relation can be moderated by the company management and the customers. The study provides both theoretical and practical implications, supporting understanding and facilitation of path changes.