I'm trying to rename HTML imported HTML webpage files. These files are 3D printer guides I've downloaded that don't easily transfer to Word or PDF formats. Some of these HTML files allow me to rename and move them to other folders, but some do not. I am not sure what the causes for this is. I can't even delete the problematic files, even though I have file deletion permission and haven't had any problems before today with any of these issues explained above. Any ideas?

As far as I can tell, my folder permissions are OK.

Here is an example file:

Here is the error I am getting for renaming:

Here is the error I am getting for moving to a subfolder: