It was reported to us that this new install manager does not, and apparently will not, have an option to install a debug Python. Which we must have to be able to build lldb in debug mode on Windows. (because the debug C runtime has a different ABI so everything in the build must use only that version) https://discourse.llvm.org/t/pythonx-d-lib-build-requirement/90285/1 Developers will have to use the "Windows installer", or build thier own, so I've linked to Python's documentation for that.