As described in a different thread, I copied an old hard disk's /Photographs directory, which I'd been using with Digikam (4.12), to a new hard disk --- all the photographs and the digikam4.db file. When I clicked on my Desktop's Digikam icon I got error messages ("No library path has been found..." and "It was not possible to add a collection to the following path...").

After I moved all of the digikam.db files elsewhere (out of /Photographs) and restarted Digikam, it generated a new digikam4.db file; all albums were now visible but only a few of them had their titles and captions. I must have copied only those albums' metadata to images.

All of those missing captions must be on the old digikam4.db file. I don't know how to get them. That "No library path was found..." message suggested "repair your configuration" but I don't know how to do that.

Hundreds of captions are involved here. I sure hope there's a way to get them back. (Kubuntu 16.04 is the OS here)