You don’t have permission to write to the folder that the file “NAME” is in.

When I save a photo from my Apple photos to my iCloud, desktop or an external drive and then open the photo in Preview to edit it, I get this error message when trying to save it: You don’t have permission to write to the folder that the file “name” is in. It says I have to duplicate the photo but that actually won't save either. This happens on all my Macs (two iMacs and a MacBook). I've checked my permissions and they all say "read and write." This only happens to current photos saved from Mac Photos and not to older photos that have been previously saved. I really need to be able to do quick edits in Preview and simply save to a folder. Any suggestions?