Purpose – We explore how experts involved in virtually organized complex problem solving balance between sharing and protecting tacit knowledge. Complex problem solving requires that multiple experts with specialized knowledge share and combine their tacit knowledge for co-created solutions. However, the personal, complex, and hard to codify nature of tacit knowledge as well as the virtual interaction make tacit knowledge sharing difficult. Secondly, different professional cultures and the lack of face-to-face interaction complicate complex problem solving. Thirdly, the individual experts may be cautious of sharing their personal knowledge in the absence of face-to-face contact, because of insecurities related to accuracy and relevance of knowledge, and be afraid of losing their future value capturing potential. Research design and methodological approach – Our research question is stated as How do experts share and protect tacit knowledge on virtual problem solving platforms? We shortly review earlier research on tacit knowledge sharing and protection. Thereafter we study individual expert tacit knowledge sharing and protection in the Case Firm Alpha digital problem solving platform. We collect qualitative data by interviewing problem solving project team members and analyse the data inductively. Value/novelty – Research on tacit knowledge sharing on virtual platforms is still scarce and research on individual expert knowledge protection even more rare. Practical implications – The topic is highly relevant for knowledge-based network economy, and the various approaches in leveraging dispersed expert knowledge across organizational and professional borders. Also, the use of digital platforms, the development of collaborative tools and increasing “freelance economy” makes understanding how to manage individual level tacit knowledge sharing and protection critical.