Files transferred from Windows XP are not visible with dolphin or ls
 

I replaced the hard drive in a Windows XP laptop, installed KUbuntu 20.04, and then copied all the user's folders and data files from the laptop hard drive. All of the user's folders, including all subfolders at all levels, are visible with dolphin or with ls from a terminal, but absolutely none of the individual files within any of the folders are visible. I would say that the files didn't transfer, except that dolphin's search function finds them!

When I did the transfer, I also copied the files to a backup drive. I can see all of the folders and files in that backup with either dolphin or ls.

If click on a libreoffice writer file displayed by the dolphin search function, the file opens with the appropriate application, so I know the file exists and is apparently intact. Incidentally, the file name is not preceded by a dot, so it isn't hidden, at not least using the usual naming convention to hide a file.

I use libreoffice to open one of the files returned by the dolphin search function, then click "file>save file as" I can see the directory in which the file is stored, but, when navigating to that folder with dolphin, I see only an empty directory.

If I create a new file in that directory with Libreoffice writer, the file is visible with dolphin and with ls. Unfortunately, I didn't check to see if simply saving an existing file opened from the dolphin search function would render that file visible from dolphin and ls.

Suggests that the transferred files need to have owner and group updated, as per those of the new file.

How can I change the owner/group if I cannot see the files in a terminal?

Did you try changing ownership with root privileges (ie with "sudo" in *buntu's case)?

Like for example:

I have still not been able to "expose" any of the files.

I am able to identify the directory in which the files reside, because, first, Dolphin's document search function (found in the left Dolphin's left panel) lists what I think is all of the files in alphabetical order, second, I can open .doc files with Libreoffice from that list, and a "save as" operation in Libreoffice reveals the path to the file. Navigating to that folder with Dolphin, however, I cannot see any files.

I ran "sudo chown <user>:<group> /path/to/files/*" on that directory, and no files were revealed.

I checked the permissions on that file. They are "drwxrwxr-x". User and group are both the same as the username.

I tried tried sudo ls -a in that directory. No files.

I tried checking with dolphin with the show hidden files option on. No files.

Again, I know that they are there, because Libreoffice can open the file and it shows the path to the file.

Any other ideas?

Just out of curiosity what is the output of the stat command for one of your invisible files?

stat file_name

I think this assumption is false.
Post some actual data.
Where is "there"?