A problem sending the command to the program

appears each time when double clicking any .comp file. I can only open an existing project through the Ctrl + O..

How to fix that?

First it appeared on windows 8.1 machine and now on my laptop with windows 10 enterprise tech preview.
Could it be windows related problem?

Seriously can't open any comp file by double clicking it!

Arrrgh.
Found the problem.
Self inflicted - self repaired:
once a poon a time for no particular reason I have set the shortcut of fusion to run as administrator in the properties tab. This tiny checker box caused this problem that it won't run any double clicked .comp file...