This study examines the formation and change of collaborative learning social networks in a distributed learning community. A social network perspective is employed to understand how collaborative networks evolved over time when 31 distributed learners collaborated on a design project using a computer-mediated communication system during two semesters. Special attention was paid to how pre-existing friendship networks influenced the formation of macro-level collaborative learning networks and individual level social capital. We discovered that pre-existing friendship networks significantly influenced the formation of collaborative learning networks, but the effect was dependent on the developmental phase of community. Also, pre-existing networks generally acted as a social liability that constrained learners' ability to enhance their social networks and build social capital when they participated in a new learning environment. The results suggest that, in order to fully understand how to build effective collaborative learning and work environments, participants' social network structures need to be considered. (Contains 2 tables and 4 figures.)