Ok so, on my machine the same issue occurs.
It seems to be related to the 3D Preview in Transmutr. Maybe there is some piece of geometry that it’s not able to process.
Thank you very much for taking your precious time.
This is not so important in my case.
The file I have had reworked.
It seems that there are some tiny elements ffsr, far away from the main structure in the fbx scene coming from 3ds max.
I have another observation.
Whilst I can place a file, drag into a Transmutr autonome program, out of dketchup with success it canot be achieved from Sketchup via plugin.
The only way to bring the file there is to browse button/method.
Could it be because when you drag the file, the mouse cursor first goes over the SketchUp viewport which makes it try to import the file?
Does it work when Transmutr is full screen?