In this paper, we aim to denaturalize a phenomenon that is too often taken for granted: the underuse of technologies. Building on ANT, in particular the research regarding unexpected uses emerging from interactions between users and technical objects (Akrich, 1992; 2006), we depart from a stage maturity perspective on technologies and initially define underuse as a reduction in the observed uses of the device compared to the original script. We report on a longitudinal study (2002-2012) conducted in a French company which is a major player on the door drop advertising market, analyzing the expected and unexpected uses of a Customer Relations Management software package over a period running from its initial design to several years after its implementation. The underuse of this CRM package leads us to question how multiple, fluctuating forms of interessement enable the network to hold up in the long run. We show that underuse of the CRM is fabricated through its uses, by discontinuation of interessement, anti-interessement and interessement that turns into de-interessement.. Paradoxically, instead of leading to controversies over the system, these fluctuating forms of interessement prevent reconsideration of actual uses. These results contribute to an understanding of why it is so difficult to reopen “black boxes”: since interest in the object remains, albeit eroded, underuse becomes established, preventing questioning of the object. We discuss the implications of our results for the accounting literature dealing with ERPs and vernacular accounting systems.