Thanks Knute
However the problem for windows (as usual) is more difficult. In addition to the PATH I needed the following to set up the association. First get check the associated name of the python file type. In an admin command prompt run the following * assoc {Python} result "no association.." * * I created one Python="C:\Program Files (x86)\LilyPond\usr\bin\python.exe" "%1" Now I look in Default Apps and there is PYTHON SUCCESS! Now convert-ly.py works I could have use something Lily specific as the association PYTHONLILY say maybe I will later. I expect I will have to do something similar if I go back to PYTHON proper. Isn't Windows wonderful ???? Regards Peter