Open innovation (OI) has attracted great interest from both scholars and practitioners during the past decades. While the benefits of OI have been examined a lot, the potential challenges of OI have been less noted and studied. This book chapter addresses potential OI challenges in (1) value creation based on knowledge; (2) innovation appropriability and appropriation; and (3) innovation network orchestration. It introduces several “what-if” considerations and discusses some scenarios where open innovation could go wrong. The chapter reminds that open innovation has both the valuable bright side, and the challenging dark side. By recognizing and embracing the challenges, risks, and costs, innovators may be able to find a balance and turn the challenges into opportunities.