I have made a box of glass and added fingerprints.
Have uploaded it to a friend's computer and the box was blurred in the viewport and render.
After a couple of days I figured it out.
The fingerprint texture was missing.
I didn't see any warning or error that warns me that the texture was missing.
You need to pack textures into the project (File > External Data > Pack Resources) or transfer them along side the blend file to the other computer. Depending on the node setup Blender will indicate issues in a shader with a bright pink color.
Blender also provides a function to check for missing files in the File menu, File > External Data > Report Missing Files.
Thanks.
I think for new users it will be good to make the "automatically pack into .blender" option, default.
I have seen the files that are missing. Is there an option to delete materials that are not used in the scene, or show what object is missing the material?