Empty/corrupt library after upgrade/crash
Hopefully it's not been too long since you last upgraded iTunes, in fact if you get an empty/incomplete library immediately after upgrading then with the following steps you shouldn't lose a thing or need to do any further housekeeping. Note that in iTunes 11 an "empty" library may show your past purchases with links to stream or download them.
In the Previous iTunes Libraries folder should be a number of dated iTunes Library files. Take the most recent of these and copy it into the iTunes folder. Rename iTunes Library.itl as iTunes Library (Corrupt).itl and then rename the restored file as iTunes Library.itl. Start iTunes. Should all be good, bar any recent additions to or deletions from your library.
See iTunes Folder Watch for a tool to catch up with any changes since the backup file was created.
When you get it all working make a backup!
Should you be in the unfortunate position where you are no longer able to access your original library, or a backup of it, then see Recover your iTunes library from your iPod or iOS device.
First time I've had this problem. I see there's a solution here and there have been others. I'll soon find out how easy--or not--the fix is.
Regardless--something like this shouldn't happen. Trusting Apple has just taken a big hit with me. Given a service with a better reputation for avoiding "glitches" like this one, I'd jump ship in a minute.
My temperature is going up. The solution above refers to "Previous iTunes Libraries." There are several files under iTunes all dated 2013 and containing the last half dozen songs I bought. *ALL* other music is no longer under "My Music." They simply do not exist on my computer.
I have not had a crash on my computer; it is a new one I bought in January--I've used iTunes on this new computer several times since I bought the new computer.
Any help recovering my music would be appreciated. Does Apple offer any direct assistance whatever, or am I SOL?