Thanks for the reply.
I thought the MC's conversion of colon ( : ) to slash (/) was some kind of a convenience feature that tried to eliminate the colon.
I didn't realise that it was actually a legacy delimiter symbol, which is being interpreted by MC as a modern delimiter slash.
I'm not absolutely positive, but I strongly suspect that MC is just sending the colon to the OSX system file management APIs, and it is being converted there:
http://stackoverflow.com/questions/13298434/colon-appears-as-forward-slash-when-creating-file-nameActually, if you read that thread, it looks like it IS preserving the colon, but that's an illegal character on HFS+, and the Finder displays it as a slash. Or something.
Even iTunes used the colon as the path delimiter as recently as iTunes 10.1. Its a traditional MacOS thing from before OSX. Now that Carbon is dead, I bet most of the applications out there have phased it out, but there is probably still some auto-correcting logic in the APIs somewhere.
JRiver probably needs to strip them out manually and replace with the "_" pre-emptively before passing them over. Colons aren't legal in filenames on Windows either, so that shouldn't be too tough.
Now, I could be wrong and this could be a bug from a misplaced effort to auto-convert from MacOS Classic-style path names (perhaps older iTunes databases or something), but then it is just a bug.