After installing Mountain Lion, my iTunes app wont start, why ???

Question

After installing Mountain Lion, my iTunes app wont start, why ??? It bounces in the dock, then "Unexpectedly Quirs"

Answer 1

Let's keep it simple...
1) Make a new user - the steps are in http://support.apple.com/kb/HT1199
2) Log into that user, open iTunes, agree, etc. - it will probably work
3) If it does, it tells us that iTunes (the program) is fine but it's encountering something unexpected
4) Go back to your user, and try to open iTunes while holding option and making a new library - like suggested in http://support.apple.com/kb/HT1589
5) Your iTunes will be empty. This is ok. Your files are not touched by this process.
6) If iTunes doesn't quit when loading an empty library, you could try rebuilding the iTunes Library as Apple documents in http://support.apple.com/kb/HT1451
7) If iTunes does quit, it could be trying to grab something - like photo information to sync to your iPad - and that's where it finds the unexpected data. Maybe try moving the iPod Photo Cache? http://support.apple.com/kb/TS1324 should guide you for how to do that.
If you tell us whether it is library-specific, user-specific, or system-wide (happens in both users), we could maybe give you better advice on what's going on.'
If the new user has the same behavior, maybe remove the SC Info folder - there are not many system-wide files iTunes touches. http://support.apple.com/kb/TS1389 covers how to remove that invisible folder.
iTunes uses /Applications/iTunes.app, /Users/Shared/SC Info, ~/Music/iTunes/ and ~/Library/Preferences/ and a bunch of other files. I don't think focusing on /Applications/iTunes/app or other system-wide files is going to be as effective as knowing whether the issue is system-wide or user-specific.
I hope this helps and feel free to reply if this is all confusing.