There is a short discussion on Apple’s discussion boards about how to make Soundcheck in iTunes run again after being cancelled. Here is a work around I came up with today (and posted to the boards):
First, export all of your custom playlists (except the smart lists that were default from iTunes) to text files one by one (File>Export Song List). Next, export your library the same way. Quit iTunes. Now, go to your iTunes folder and delete the “iTunes 3 Music Library” and “iTunes Music Library.xml” files.
Start iTunes and it will be empty. Import the text file for your library that you exported. Once that finishes exporting, the soundcheck will run. Let it. Once soundcheck finishes it’s scan, you can now import your playlists. You will also notice that importing the library file re-created your library, but also created a playlist called “Library.” You can delete this. Voila. You entire music library soundchecked and all your playlists back!
One note: after importing the library text file, you may get a message that some of the MP3’s could not be imported because they could not be found. Don’t worry about it. It’s just the header row for the file causing the error.
