Okay, try not to panic. There are two things to try.





First, you should try to turn off iTunes in the Cloud, which I think requires going into Store > Account Info and selecting "Deauthorize This Computer" or something like that. (I can't check because I've got it turned off.)





Now quit iTunes. Look in the folder Music > iTunes > Previous iTunes Libraries. Hopefully, there is at least one document in there with the file extension .itl and a date *prior* to when you updated to to 12.2. If you find such a thing, then do this:





Back in the main iTunes folder, rename the files iTunes Library.itl and iTunes Music Library.xml (just add "corrupted" to the beginning of the file name, or something like that). Now rename the previous version to iTunes Library.itl, drag it into the main iTunes folder, and restart the iTunes app. (The XML file should regenerate automatically.) If all goes well, you should be looking at a version of your iTunes with all your playlists and songs restored. If you are given the option to use iTunes in the Cloud, just say No -- this seems to be where these problems are coming from.





If you can't find such a file, then you can look for one in TimeMachine -- just be sure the backup was made prior to upgrading to 12.2. Again, bring this into the iTunes folder, replacing the version that's been corrupted. I really do hope this works!





I hope Apple has taken note of this nightmare and is working on a fix.