This paper describes a qualitative research study that surfaced practitioner interpretations (assumptions, knowledge, and expectations) of applications integration downsides. Although integration is the primary benefit of enterprise systems, like most things, integration also has a downside. However, most people agree that integration is still desirable. The challenge is to understand and manage the negative aspects of integration to minimize the adverse effects. Doing this requires an awareness of the potential problems. This paper augments past research on this subject with the results from a recent investigation of integration of applications for enterprise systems. Fifty-one people representing three stakeholder groups from four organizations were interviewed. The data revealed thirty-one unique integration downsides representing at least five dimensions. It now appears that integration is not always desirable or practical for a number of legitimate reasons. Collectively, organizations spend billions of dollars to achieve integration so it seems reasonable that understanding applications integration downsides is important to success. Yet, little is known about practitioners? perceptions of integration that influence their decisions and actions.