Preview image crude hyper pixelated for 3dm containing just a dwg

V5. win7 64bit pro.
I opened a dwg into V5 and saved the file. Now I come to open it using the v5 splash screen and open tab, the preview pane has a very rough pixelated image of it yet another 3dm with it and rhino native curves as well has a fine clear image.
Likewise same if I use file>open to browse to it.

why is that ? what settings will clarify it ?

Also, …anyone know of a way of getting windows explorer to thumbnail dwg and dxf or even 3dm files ideally without registry hacking as I dont want to mess with registry whilst still evolving this win7 pc, my engineer also wont be too keen. Wish Bill Gates was to catch up with the world ! Win7 wont even thumbnail photoshop psd files within the pshop file open window ! Thats like rhino not previewing its own files. Well done McNeel on that one at least, score Adobe 0 Mcneel 1 referee B Gates warped ! :slight_smile: