Darren, thanks for pointing out these VIs! It appears that the problem with the OpenG VIs is in the "Array to Array of VData" conversion, this VI is attempting to convert an array contained in a single variant to an array of variants. The method used, a NI "Variant to Data" VI without the type input wired doesn't seem to work when the array of clusters is empty. Although, I'm not sure how I would do it any differently. It would seem that this should be made into a bug report, if one doesn't already exist.