Ha! my pet topic. Alas the solutions proposed previously won't work when LabVIEW is already running...
The trick is to build a small executable and then associate the file extension to it. This small application, reads the file path from the command line and then launches LabVIEW (if necessary) and runs the appropriate VI using the VI Server. That requires the TCP VI Server be enbled on LabVIEW. The launching applications then quits and is ready for the next call. Jean-Pierre Drolet Avensys
