Hm that’s weird. You can also choose to manually install a PIO core via PIP (sudo -H pip3 install platformio) and then set the VSCode extension to “not use built-in core” (there’s a checkmark in the extension settings). Can you try that? Also note that the latest VSCode version is known to have some problems, so 1.39 is advised (PIO, VSC can't build, no tasks found)