Thumbnails

Hello,

I produce files for 3D printing when I save them I save them as .3MF files on a windows PC.
In the past all my saved files had a thumbnail view, now none of the newer saves have this, they just have a title and blank picture icon.
What happened to the thumbnail images?
The older ones are still there, I haven’t changed any settings!
Its so much easier to find the file you are looking for with a picture of the design.

Thanks