Copied or moved PDF files will not open

When I receive a working pdf file to my Downloads folder, I am unable to move it or rename it. Trying to open the new file leads to a message saying "The file --- could not be opened. It may be damaged or use a format that Preview does not recognize". I can use the Finder menu to make a duplicate (copy) in the Downloads folder and it will open. But the moment I move the duplicate (or original) from the Downloads folder it no longer works.

If I create a new pdf, say from Pages or using Print>Save as PDF and create that pdf in a folder anywhere else (say to Documents) it also is unable to be moved from the folder it was created in (Documents in this example). So the problem occurs anytime a pdf is moved from its original location.

This seems like an Adobe thing but maybe my dislike of Adobe colors my suspicions.