In dynamic business environments with uncertainty and risks entrepreneurs make efforts to customize new products to latent user needs. In a product development process, user/customer integration (an approach of giving users an active role in an innovative product design) relates to challenging processes of collaboration and knowledge sharing with and within an entrepreneurial team. The paper research is focused on a model that comprise knowledge conversion and knowledge sharing barriers in an entrepreneurial team working in collaboration with innovative and “ordinary” users at early stage of product design. The key barriers to knowledge sharing in collaborative entrepreneurial team were formulated and assessed based on qualitative research (observation, questionnaire, and in-depth interviews). At the early stage of product design, in the model of knowledge conversion in collaborative entrepreneurial teams, the role of exploratory prototyping is identified.