I put my entire iTunes library onto an External HD to free up space on my main HD, and it works fine until I unplug it. I usually quit iTunes, unplug it and then plug it back in before I open iTunes again. But when I open iTunes again, it changes the location where it looks for music back to the default, instead of using my setting. Then it says that all of my music has to be relocated and it puts the "!" symbol next to a lot of the songs. It goes away by just playing the song, I don't even have to locate it, but this is annoying. Any way to prevent this?