Thanks Mohammadreza. I finally solve the by combining Mohammadreza and Carmichael's experience. Here are my solution: Mac M1 13.2.1 python 3.8.8 step1&2&3: conda create -n opensim_py38 python=3.8 conda activate opensim_py38 conda search -c opensim-org opensim then you can see: Loading channels: done...