A new frustrating issue started recently. When I move or copy any Dropbox file, of any type, to another folder - even another Dropbox folder - I now get the daft message shown below. I repeat: these are local files, made by me, owned by me. After testing it seems that this only happens when the initial folder is in Dropbox. I can move or copy files outside Dropbox into a Dropbox folder (or any other folder) as usual, with no silly message.
Thanks Daphne, but after much further research I'm now convinced this issue is about my internet security options and I'm focusing on that. Some of the zip files in one large folder I've isolated generated similar warnings at the time they were downloaded. I accepted the warnings and have had no problems using their unpacked files - except for these further unwanted warnings whenever I want to move or copy them. Thank for your help. Pretty quiet here otherwise! 😉