Block Instance Material Conflict Dialog Slow on W10 fine on W7

Hi, I came across a weird issue regarding block instances upon opening a Rhino file… This could be a Vray problem or Rhino, I’m not sure.

You get a dialog asking if you’d like to use the existing scene material, replace the existing scene material or to rename the material and whether you’d like to do this for all subsequent conflicts for that block (to Apply All).

After selecting one of the options CPU usage goes to 100% and it takes about a minute to show up again for another block.

On W7 Machine (much older and way less powerful) dialog shoes up almost instantly.

Both machines are connected to Qnap NAS over 1G cable.

Even stranger is that after updating the NAS to current SW it ran OK on W10 too. But after a day or so it became slow again.

Does anybody have a similar issue? Or a suggestion on how to fix it?

I have up to date Rhino , W10 and Vray 3.6