Q: After moving my iTunes library to an external hard drive can I delete the media off of my computer?
A: Assuming that you have moved your iTunes library to an external hard drive via the “Consolidate Library” function, as described in our article on Managing your iTunes Library on an External Hard Drive then the media left behind in the “iTunes Music” folder is no longer being used by iTunes and can be safely deleted.
To err on the side of caution, iTunes always copies files when performing library consolidations or adding new tracks into the iTunes Music folder. These original files end up being left behind as the responsibility for the user to clean up once they have confirmed that the files have been properly moved or imported.
You can spot-check your iTunes library to confirm that your library has been properly updated with the new track location simply by selecting a track and choosing File, Get Info. The “Summary” tab will show the full path to the selected track at the bottom.