Hi Mr. Smith , Thank you very much for your prompt reply. As instructed, I changed my own environment (anaconda) and executed it with the latest yt ( yt   4.0.1 py310hb5077e9_1 conda-forge), referring to the following URL. https://yt-project.org/docs/dev/installing.html However, the error did not improve and I got the same one.... If you have anything else to try, please let me know. Tomoyuki