iTunes for Mac won't open or unexpectedly quits
Symptoms
iTunes does not open or quits unexpectedly, or a message appears that says the library file is not a valid library file.
Products Affected
iTunes 7 for Mac, iTunes 8 for Mac
Resolution
This could be caused by an unusable iTunes Music Library.
Recreate your iTunes Music Library file.
Note: If iTunes continues to unexpectedly quit, check for add-ons which can cause this issue.
Additional Information
See the articles below for more information.
iTunes for Windows: Troubleshooting unexpectedly quits, freezes, or launch failures
iTunes for Windows doesn't open after upgrading
iTunes 6 won't open on a Windows computer if firewall software is not up-to-date
iTunes 6 for Windows unexpectedly quits when opened