When I try to invoke the tkinter module in Python 3 that is bundled with Xcode Developer Tools, I get a message saying that my system version is too low: $ /usr/bin/python3 -m tkinter macOS 26 (2602) or later required, have instead 16 (1602) ! zsh: abort /usr/bin/python3 -m tkinter It seems like the system version reported is macOS 16, which I assume is the version code before the decision to rename all OS platforms to 26. This is a very low level mistake and should be fixed as soon as possible.