FD12 and 11 open FD10 / 9 / 8 files directly. You should be able to simply double-click on a script file icon and it’ll open in FD12 / 11, if that is the most recently installed version of FD on the computer.
There is no need to copy and paste any content from a script into a blank FD12 / 11 document.
If you have FD12 / 11 installed and when you double-click on an FDX script icon it opens in FD10 / 9 / 8, the file association needs to be reset:
If you have Windows: http://www.thewindowsclub.com/change-file-associations-windows
If you have Mac: http://www.laptopmag.com/articles/how-to-change-default-applications-mac
You can also open FD12 / 11, go to File Open and open older scripts that way.
2006
https://fd.support/42xLPp8