iTunes 12.2 update reverted 22,000 songs' worth of metadata. Now what do I do?

Actually, I have a pretty strong backup plan. I have a separate backup on my backup hard drive that remains locked. I also keep two compressed versions of each album—one on another hard drive and one on a separate cloud service. I'm not actually sure what your original comment has to do with my actual problem. If you have a technical explanation, I'd love to hear it.

Please see above for backup plan and follow-up question.

I use the standard, long-form iTunes plug-in by metadata by hand method that everyone else uses. Thanks for making assumptions about my methodology, though.

The reason I have to muck around in the metadata is that I often download songs and albums directly from artists and their labels through services like the Free Music Archive, Soundcloud, and other legitimate and legally-sanctioned services (Bandcamp, et. al.). Often artists and labels will be rather lazy about creating even the basic metadata for their music, especially if they're giving it away for free. Even when I purchase music through Bandcamp and other direct-to-listener services, I often have to go in and tweak basic information. This is not something I do for fun, I can assure you.

Again, I'm curious as to how you think chastising me for imagined technical ills has to do with my original question. If you have a technical reason for these responses of yours, I'm willing to hear it. If not, jog on.

I'm using the standard, boilerplate "Get Info" metadata information. I typically change basic things like accidental misspellings in titles; I tweak non-uniform band names (guess how many ways "Edward Sharpe and the Magnetic Zeros" can be misspelled); and I resqequence outrageous numbering errors. Plus, many of the bands I like tend to invent their own whimsical genres, so I have to change genres to something more recognizable.

The music I listen to is either so new that iTunes doesn't sell it yet, which means I'm defining the metadata for any users who come after me—or it's new and rare and will never be sold by iTunes—or it's not sold in the US or UK iTunes stores, but is sold in country-of-origin iTunes stores and the metadata isn't being shared out. I don't even know how to alter DRM data. I still buy vinyl, for cripes' sake.

What's happening is—and this is key—iTunes is reverting back to whatever non-edited version of metadata it originally reverted and uploaded when I tried out iTunes Match . . . . This would be understandable if I was logged into Match on any of my devices, but it's happening when I'm totally signed out of Match, have dumped the wrong library and reinstalled an earlier correct version, and everything is going just fine until I sign into my Apple ID on iTunes and it reverts again. And before anyone askss, let me tell you that I did not and will not sign up for "Music in the Cloud." Considering how useless Match turned out to be for me, why would I compound that mistake with some newer, untested version of the same thing?

What I've decided to do is delete my iTunes library and reinstall it by hand from my backup while I'm signed in. It appears to be working—all of my original metadata corrections are showing up properly. It's just slow going. It took me three hours to get through all of the "A's." I'm really sick of these grotesque upgrades to software that barely works as designed to start with.

I'm also a Mac user from the way back! Nice to meet you!

How have you been managing since they changed the metadata order from the last update? It's really throwing me off, especially when it comes to plugging in composer information!

Do you have some sort of Time Machine set up for your current computer? Have you tried dumping your .itl and .xml files with iTunes shut down and replacing them with earlier undamaged versions from a Time Machine backup? If you've done this already, may I suggest you sign out of iTunes and try it again?

It just occurred to me that if your actual library still contains all of its tracks, you might be able to skip rooting through your backups and just sign out and dump your .itl and .xml data sheets, then reopen iTunes and let it recatalog itself. Signing in seems to trigger the messed up recataloguing behavior —the only fix I've found for that problem is the extremely tedious sequence I've listed above.

Bah! I'm so sorry this is happening to you. And with a library three times the size of my own, no less! I can barely imagine it!

if you merely want to find your immediate 16 missing mixed tape tracks, can you just do a Finder search and reinstall those?

*Slaps forehead* It just occurred to me that you already said that you tried rebuilding your library once and it only catalogued 9000 items out of 50,000+. Please excuse my stupidity.

Can I ask if you were you signed in at the time when you rebuilt your library?

Let me also point out, again, that I said I was changing the standard metadata three times now. I'm sorry that this information appears to be difficult for you to grasp. I hope that my lengthy, detailed answer allowed you to wrap your mind around the precise details of my metadata changes—a discussion that is not significantly relevant to the problem that I am attempting to dissect. Also, please excuse the three spelling errors of my previous answer. Apple was attempting to "help" me when I was typing that reply on my iPhone.