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what other information do you need?

13.3 mbp
snow leopard
4gb ram
i use vlc to play my music, but happens even when i use itunes to play it

I'm not sure I can be of any help here or not, I've never used VLC to play music. As far as iTunes, under Preferences, Advanced, top section is option for Copy files to iTunes media folder when adding to library, if this is checked and you double click a file outside of iTunes, like in the Finder, it will copy it to the iTunes media folder. If double clicking a song from within iTunes it should just play it as it's already in the media folder. Could this be what's happening?
 
I watched the video and I have to say that I've never seen that happen before. Does it happen with any other type of files?
 
Is this something that just started? Are the music files on the same hard drive as your Mac is booting from? Do you have any kind of add-ons installed?
 
I think it's what DewGuy1999 pointed out. You are aware that everytime you double click a music file which is by default connected to iTunes adds it to its library? So if the folder you showed in the video is in the iTunes Media Library Folder and copying is turned on in the settings, then iTunes copies it over and over again to that folder, as it is supposed to.
 
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