Unfortunately you didn't include the entire command-line and the whole log. In general, this VS error indicates that VS cannot find the required include files. You either didn't run it from the "Developer command prompt for VS 2022" OR you don't have the the correct SDKs of Visual Studio installed, OR the PATH variable is borked in some way.. There are several workarounds: Option A: use a Python version from that time period. In my tests Python v3.9 works out of the box and doesn't even need VS Build Tools. Option B: change version requirements for the project: 1) make a folder for unlicense, say c:\projects\unlicense 2) open command prompt, change to that folder and clone the unlicense repo there: git clone https://github.com/ergrelet/unlicense.git . Or just download ZIP and unpack it into that folder. 3) edit pyproject.toml to change versions of python packages. For you, the most important is the xxhash version, pick one where there is a pre-compiled wheel file available for your version of Python. I'd use "^3.6" there, it seems to be compatible. If that does not work, try "^3.1", that's the oldest version with a pre-built v3.11 wheel. That should be enough for you. 4) run pip install . - it should run build process, find the pre-built packages in PyPI and happily use them, instead of compiling xxhash from source. Option C: try installing/building xxhash package and figure out what went wrong. Ain't got no time for that..