Many organisations have implemented or are implementing large enterprise systems, like ERP and PDM, for integrating their business functions and streamlining the flow of information. Implementing such systems is very complex, however. In many companies the results envisioned have not or have only partly been achieved. In the literature many explanations can be found for insufficient or failing implementation efforts. A large part of the problems encountered appears to be human and organisational in nature, while it has been stressed that implementing an enterprise system requires and involves organisational change. Success and failure factors and do's and don'ts, as can be found in the literature, provide necessary, but not sufficient, preconditions for starting an implementation project. The complexity of such a project makes full anticipation and control of potential problems impossible. An organisation needs to be prepared to encounter disturbances and take corresponding actions. Knowledge on the dynamics of enterprise system implementation processes is, however, scarce and scattered. Moreover, to what extent the context in which an enterprise system is implemented influences implementation is not yet fully known. In this article, an approach is presented to gather knowledge on implementation process dynamics. The approach builds on theoretical and practical contributions in search for a structured human and organisational approach. The knowledge gathered has been analysed by means of a comprehensive reference framework. After this step a tool has been developed to support a consultant in assessing the maturity of a company to start an enterprise system implementation project. The knowledge, used directly in the tool, makes it possible to suggest improvement actions sensitive to the situation and context. Through statistical analysis, interesting context differences have been identified, which may also help in further refining the advice. Initial validation results are promising.