To install PolyFX, do the following:
- Run 3ds Max as administrator.
- Drag "PolyFX_*.mzp" file in viewport. If you can not drag the file, run the "mzp" file through menu bar "MaxScript (or Scripting) -> Run Script" on the top of 3ds max window.
- Press "Install".
- Restart 3ds max to completed.