My file association for .dwg is set for IntelliCad but I can't get the Windows folder preview to show anything when a file is selected in the folder list. How can I fix this? Thanks!

Please check your setting, here's the preview on my PC.

and the Thumbnails mode:

My preview is turned on and other filetypes show in the preview area but .dwgs do not show preview, my file association is set where .dwg=icad.exe. I don't know what else it can be?
Thanks...

It's doing something very odd now, some drawings in some folders have previews, I thought maybe there was a setting that determines it but I have not changed anything. This is strange, if I copy a file that has a preview eg. bike.dwg to bike - Copy.dwg, the copy should have a preview but it does not! It makes no sense.

Maybe not compatible between the different CAD software!!!
Try the drawings saved by IntelliCAD instead only.

I only have Intellicad installed. After that test (bike.dwg) when I copied the file that didn't have a preview, a minute later I came back and it had a preview, it makes no sense.