Purpose The purpose of this research is two-fold: (1) to investigate the challenges e-tailers are confronted with when synchronizing clicks with bricks into an omni-channel perspective and (2) to shed light on the possible ways to overcome these challenges in order to successfully implement an omni-channel strategy. Design/methodology/approach To answer our research questions, we draw on an in-depth longitudinal case study conducted within the French on-line eyewear retailer Direct Optic from January 2013 to March 2015. From an ethnographic perspective, we document the evolution of the retailing company’s decisions and processes as they moved towards defining and implementing an omni-channel strategy. Research was carried out using primary (1500+ hours of participant observation and 118 interviews) and secondary data sources. A conceptualizing content analysis was conducted both manually and with NVivo software. Findings First, our results show that the challenges faced in shifting to omni-channel strategy are so numerous and so engaging that, de facto, it is impossible to evolve directly from a multi-channel, siloed strategy to an omni-channel strategy without any transition. Second, throughout this transformative process, our result show that the challenges faced by the company evolved gradually in terms of scope and priority, and can be categorized into two main categories: the strategy-related challenges (organizational, cultural, managerial, marketing and resources) which were the highest priority in the first stage and the development-related challenges (retailing mix, information systems and CRM) which became the highest priority during the second stage. Research limitations/implications We emphasize the importance of carefully orchestrating how strategy-related and development-related challenges are addressed as, for retailers engaged in going omni-channel, this involves a complete transformation of their configuration. Originality/value Our study contributes to channel management and retailing research by (1) deepening the conceptualization of multi-, cross- and omni-channel retailing, (2) exploring the nature, importance and sequence of the strategy-related challenges and development-related challenges when shifting to an omni-channel strategy, and (3) providing insights into how successfully navigating the transformative process to be omni-channel requires investigating different possible solutions, and further testing and re-testing them, before deploying the appropriate ones. Up to our knowledge, it is one of the first studies to empirically investigate the challenges of an e-tailer when moving towards an omni-channel strategy.