This error means that clang is not installed (or if you did, you might have to restart your PC, because it changed environment variables, and windows is pretty annoying with updating that) https://docs.ficsit.app/satisfactory-modding/latest/Development/BeginnersGuide/dependencies.html#ClangToolchain You could also disable building for Linux Server in Alpakit for now, but it is expected that all mods support both client and server (both OSes), unless they are incompatible with it, so you should fix your clang for building for linux