In this paper we set out to investigate how an Enterprise System (ES) adaptation in a Scandinavian high-tech organization, SCANDI, can be understood using a combination of institutional and sensemaking theory. Institutional theory is useful in providing an account for the role that the social and historical structures play in ES adaptations, and sensemaking can help us investigate how organizational members make sense of and enact ES in their local context. Based on an analytical framework, where we combine institutional theory and sensemaking theory to provide rich insights into ES adaptation, we show: 1) how changing institutional structures provide a shifting context for the way users make sense of and enact ES, 2) how users’ sensemaking processes of the ES are played out in practice, and 3) how sensemaking reinforces institutional structures.