A growing part of the literature on crises, disasters, and policy failures focuses on the design, conduct, and impact of postincident reviews or inquiries, particularly whether the right lessons are identified and subsequently learned. However, such accounts underappreciate the specific challenge posed by epistemic puzzles, under what conditions their difficulty may vary, and which strategies could help to solve them. Drawing on insights from a wide range of cases, the article identifies hindsight bias, counterfactual reasoning, and root‐cause analysis as core components creating an epistemic triangle of inquiry puzzling. It advances four propositions about the conditions that help or hinder investigators' capacity to produce sound knowledge and concludes by setting out potential strategies that investigators can use to fully address or at least mitigate these epistemic challenges.