Students' prior knowledge may affect their learning of content in a compulsory Indigenous Studies course. Notably, non-Indigenous pre-service teachers' prior knowledge may bring conceptions and misconceptions to their formal Indigenous Studies education, potentially influencing their engagement with and/or resistance to concepts affecting their manifestation in their future classroom practices. Indeed, learning, unlearning, and relearning often occur in Indigenous Studies courses. Accordingly, this research aimed to understand what formal and informal knowledge students bring with them to their university studies to improve pedagogy. The survey data were collected from 357 pre-service teachers commencing a compulsory Indigenous Studies university course over four semesters. This analysis revealed two distinct clusters -- those who valued their formal schooling knowledge ("Formal" cluster) and those who valued their personal experience-based knowledge ("Informal" cluster). Unlike the "Formal" cluster, the "Informal" cluster held extreme views of social media as a source of knowledge and were more likely to disagree that their prior knowledge is limited/incomplete. Interestingly, institutional and individual factors such as gender, as well as exposure to enduring discourses, were also important but need further research. We argue that university and school educators need expertise in identifying prior 'troubling' knowledge of students and integrating knowledge sources to more skilfully 'trouble' and transform student knowledge.