Windows cannot access the specified device, path or file. You may not have the appropriate permissions to access the item.
Having tried elevated console with various commands (e.g. secedit), modified file permissions through Roles and Access, reinstalled Windows (on the main SSD, whereas all the date resides on other Data hard drives) – still no luck.
Windows generates thumbnails for images, it will let me use them if I drag them to the likes of Skype or online services like Google Drive. So there’s a cloud-based Workaround, or I could explore the likes of file recovery software, but first I’m going to try copying files over to a clean hard drive, then formatting the originals.