Prior research with regard to the relationship between system use and job performance has been inconsistent. Some research found that system use has significant impact on job performance, as anticipated; other research does not confirm such a relationship. In this paper, we try to bridge this inconsistency by attributing this inconsistency to the simply conceptualized and measured system use construct. Subsequently, we introduce a "richer" conceptualization of system use, namely adaptive system use, and we examine its relationship with job performance. We suggest that adaptive system use accounts for a significant part of the impact of system use on job performance. Using a sample of 274 MS Office users, we were able to confirm that adaptive system use has significant impact on task productivity, management control, and task innovation. This research has implications for both research and practice.