Based on an interpretive case study and Activity Theory as a theoretical framework, this contribution shows how local users of an enterprise resource planning system in a Chinese joint-venture of a French multinational corporation have developed an informal organizational structure which eventually led to workaround work practices. The development and quest for alternative practices was justified as indispensable and appropriate to respond to local needs. In that perspective, the formal structure was not sufficient to cover the problems met at the Chinese subsidiary. Our research tackles an original aspect of post ERP implementation since it suggests that informal work practices might eventually lead to the adoption of global IS.