When I look at iTunes, the app says I have 9.53GB of music, but in the actually iTunes library folder (stored on my external drive), it says I have 19GB on music...
if i had to guess, i'd say your itunes is making a copy of your music and placing it in the itunes folder of your music folder. untick the checkbox in the preferences and delete the extra files.
When I look at iTunes, the app says I have 9.53GB of music, but in the actually iTunes library folder (stored on my external drive), it says I have 19GB on music...
Does that figure include any videos that you may have. If you have 'Music' selected from the Library then it won't show any videos/movies that you have managed by iTunes.
Of course if you knew that already then perhaps you just have 2 copies of every single song in your library? Sorry I can't be any more help.
If you only have music, with no album covers, in iTunes then the difference must be all the indexing (artist, album, etc.) and whatever metadata is associated with your music (track, etc.). No matter how you backup it should only appear once on your backup drive. If 19GB is a substantial portion of your drive, it is time for a larger drive. Best wishes.
Is it possible that there is stuff in that folder which is not in your library? Like other files hidden in there somewhere? you may have saved something there which is not music or iTunes related? If it's a huge deal, Maybe you should go through the folders in the iTunes music folder and see if any of them are unusually large.
May I recommend WhatSize http://www.versiontracker.com/dyn/moreinfo/macosx/21149
It'll help narrow down what folder you have unaccounted files in.
I agree with Mankar that there are music files or random files in your music library that are not in your iTunes Library.