First post because I had the same issue and found simple fix that I think others may really want to know. Through another program i found out that the error number is error 48 ...
dupFNErr |
Duplicate filename (rename); File found instead of folder |
This is probably obvious to you but another user posted that this is the issue...
"I have discovered why this happens. In every case, the folder that generates this bug has items inside it that have identical names except for differences in capitalization. For example, the folder "Metallica" has one subfolder called "Master of Puppets" and another subfolder called "Master Of Puppets". Apparently iTunes is (or some former version was) case sensitive in creating folder names for albums. That case sensitivity seems to confuse the Finder, causing this confusing error. In the case described above, the error would be, "The operation can't be completed because an item with the name 'Metallica' already exists." As you can see, this makes no sense at all, since it is actually the subfolder that has the same name, but the parent folder that the finder references in the error.
So the solution (for me) was simply to open the folder that is referenced in the error, make sure you are sorted alphabetically, scan through the list of subfolders (in my case it was always a subfolder) to find the duplicates, consolidate the items into one of the folders, and delete the errant folder. "
FIX:*****So basically there is some confusion with the file name, could be two file names with same name but some letters are capitalized while others aren't (making the program think that there is a file with the same name). My case, however, was solved by renaming a file that had a tilde ('~') symbol (Presuming that this is a special or reservered character that cannot be handled by OSX). I dont know why the symbol is there but I did not need it and it caused problems so I renamed the file without the tilde (~) symbol. Then I attempted to copy files to my external hard drive with no issues. If you have a large quanitity of files this could be a little more difficult but what you can do is go to the folder in which the error message claimed contained the same file name and you open the folder and use the Finder search bar to search for any files that have the tilde symbol (~) in it. (to search this, just type a ~ into the search bar. Hopefully you will not have many files like this to rename).
I also wanted to point out that in my case I did not need the tilde symbol (~) to use the file with my program which is actually just a song file I use in itunes, but if the program you are using requires a tilde symbol (~) to recognize/use/play file then obviously you may want to reconsider whether it is a safe idea to remove the tilde symbol from the filename. I guess if it didn't work then you could always add the symbol back into the file name. I don't think removing the tilde symbol would affect functionality of the file but I am not sure and wanted to put a little disclaimer. But if your issue is an mp3 file then you can assume that its safe to remove this tlde symbol.