To install PolyFX, do the following:

  1. Run 3ds Max as administrator.
  2. 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.
  3. Press "Install".
  4. Restart 3ds max to completed.