The registry edit I made is the same thing as the fsutil command you posted Bitt.

But, thanks for the renaming tip. It lead me to discover some more information.

Arrrgh.

What appears to be the main issue is that the filenames are in fact NOT using the correct unicode characters. The cedilla for instance was made up of two characters in the problem names. If I copy and paste this to Mac OS it looks fine. But isn't the same thing as when I type it properly.

So for instance can type a filename into a mail message with the correct cedilla "ç" and then paste the Windows name directly under it. Both look identical. Only the one I typed can be pasted back to Windows and work correctly.

What I'm doing to fix the mp3 filenames is running a process through MP3Tag to rename the files based on the tag text. It handles the unicode properly so far and omits invalid characters. Easier than writing a script to recursively traverse my filesystem.

The same problem existed for "Maxïmo Park" while "Tïesto" was working fine. Looking carefully you can actually see (in Explorer) than the umlaut above the i in Maxïmo was slightly offset to the right. Two characters. One i and one umlaut. Weird.

The 8.3 might have been a wild goose chase after all, and only an issue in representing the long names because of the oddball characters that were within them.

I'm still going to have to do some manual searching for any folder names affected, because the tag-to-filename process is only touching the files.