Now I have installed Rhino on the VM, and reinstalled the GrassHopper Template, but still the same problem. The (GHTemplate) install log says (the row marked with * drew my attention) :
2017-06-07 16:33:53 - Searching for applicable products...
2017-06-07 16:33:53 - Found installed product - Microsoft Visual Studio Community 2015
*2017-06-07 16:33:57 - The extension with ID 'DAD17ACF-0A09-4FE0-B2F0-6E37A1C3CB03' is not installed to Microsoft Visual Studio Community 2015.
2017-06-07 16:33:57 - Found installed product - Microsoft Visual Studio 2015 Shell (Integrated)
2017-06-07 16:33:57 - Found installed product - Global Location
2017-06-07 16:34:06 - The following target products have been selected...
2017-06-07 16:34:06 - Microsoft Visual Studio Community 2015
2017-06-07 16:34:06 -
2017-06-07 16:34:07 - Beginning to install extension to Microsoft Visual Studio Community 2015...
2017-06-07 16:34:07 - Install to Microsoft Visual Studio Community 2015 completed successfully. The extension has been installed to C:\USERS\ROLF\APPDATA\LOCAL\MICROSOFT\VISUALSTUDIO\14.0\EXTENSIONS\04XJIN1T.IWP\
Some crap left from earlier install attempts? Perhaps some fiddling with the Registry would do? (Installing VS on my work horse isn’t really an option since I’m running out of space)