Hi Josh, Due to recent changes in ChimeraX, you now need to add "format mole" to the "open" command and it will work as it should. For example, "open browse format mole" instead of just "open browse" as shown in the tutorial, or "open yourfilenamehere.json format mole" if you're just opening the file directly instead of browsing to it. I submitted a bug report, ticket #15486, including your email address so you will get notifications if anything happens with it. I submitted it before I realized that opening the file would still work if you just include "format mole," so maybe it's not really a bug. In the meanwhile I will change the tutorial to include "format mole" in the open command. Best, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco