Yo, Go to Edit>Preferences>Advanced in iTunes, are the "Keep iTunes Media Folder Organised" or "Copy files to iTunes Media Folder...." options selected? Basically, if the latter IS ticked then you'll already have two copies of everything, so if you delete it all from your iTunes Library (keeping files) then re-add everything you'll end up with duplicates ahoy. Best thing to do is if you've got the time, ignore the iTunes Library for now, bung all the actual files in one place (on an external HD would do it, extra bonus of a backup) if you're completely certain you have everything, delete your iTunes Library in iTunes (select all your music, hit Del, keep files when it asks) then go and delete the contents of your iTunes Music folder (if you wanna save podcasts, they live in that folder, in a folder called Podcasts, so dont delete it if you wanna save downloading again). Now you're clear of your library and all your stuff is safe, either untick both those selections i mentioned above, then just File>Add to library>choose folder containing all music. OR Slightly more complicated but you could create a folder called iTunes (or whatever you fancy) on your external HD, make it your "iTunes media folder location" under the advanced tab mentioned earlier, tick both those aforementioned buttons then add all the music to your library. Then it will copy it all and arrange it all into some kind of order whilst keeping it on your HD away from your computer, and every time you add music going forward it will copy it and organise it in the iTunes folder. - Only bugger with this one i found was if you unplug your Hard Drive on a regular basis and it gives it a different drive letter, it wont be able to find where your Library's stored and ALL your music will come up with the wee "could not find" exclamation mark. Pain in the ass. Yeah, i get a bit Trinny and/or Suzanna with my Music Library. Hope you get it sorted!