The main goal of this study is to identify and better understand barriers to enterprise system (ES) adoption success. Drawing from the experience of a few dozen ES adopters from Poland, this study identifies and categorises barriers into coherent groups of issues. They are next analysed taking into consideration respondent role in the ES implementation. Subsequently, this internal stakeholders’ perspective is compared with an external viewpoint by mapping this study’s results onto the outcome of the research work discussing the external experts’ standpoint as regards difficulties occurring during ES projects. Next, the analysis relates its findings to the problems reported by prior research conducted in developed countries. The results illustrate that among the many barriers experienced by ES adopters the most important are connected with infrastructure, time, cost, and knowledge. They also emphasise the need for incorporating multiple stakeholder perspective in order to gain full insight into ES adoption. The paper ends with conclusions and recommendations for researchers and practitioners.