iTunes gets criticized a lot. For its interface, for its over-abundance of features, and even for its name. (It hasn't just managed "tunes" for a long time.) Since I write the Ask the iTunes Guy column here at Macworld, I have opportunities to delve into the intricacies of iTunes, and field questions from befuddled users.

I generally accept iTunes' quirks, though I don't hesitate to point out the most egregious problems in the app. But I update to every new version, in part because I write about the software, but also because iTunes is an app I use a lot, to manage and listen to my Brobdingnagian music collection.

Until now.

If you have a carefully curated music library, manually tagged, with painstakingly chosen or scanned album artwork, stay away from iTunes 12.2.

iTunes 12.2 is a disaster. The Apple Music features are confusing at best; the way iTunes Match and Apple Music work together is problematic ; and, worst of all, many users are finding that it destroys music libraries.

I did update iTunes on my MacBook Pro; my test computer. It has a small iTunes library, which, together with my iTunes Store purchases, comes to about 9000 tracks. But I won't upgrade my iMac, which is where my large music library (around 65,000 tracks) is stored.

The biggest problem with iTunes 12.2 is the iCloud Music Library feature, which combines iTunes Match and Apple Music, as well as your purchased tracks, giving you access to music across devices. This is a great idea, in theory, but iTunes Match has been fraught with problems since its launch, and the iCloud Music Library is simply broken. On my MacBook Pro, iTunes messed up my album artwork, changed tags for a lot of my music, and converted many of my Matched and Uploaded tracks to Apple Music files, which, if re-downloaded, contain DRM.

It was bad enough when music I synced to my iPhone displayed different album artwork, and when different tags started appearing on my music after syncing. But this is too much.

My music library is sacred. I've ripped a few thousand CDs, tagged them very carefully, and added artwork to every track in my iTunes library. Changing my metadata or changing my artwork is a violation of my music library. It's as though someone came into my house and rearranged all my books, substituting paperbacks for some of the hardcovers, and replacing some books by versions in different languages.

Kirk McElhearn iCloud Music Library has replaced the existing artwork with covers that are wrong and seemingly out of left field.

Sure, call me obsessive. Back in the day, I was one of those guys in the record store in High Fidelity. I love music, it's very important to me, and the time I've spent maintaining my music library shouldn't be erased by some faulty software. Especially because there is no reason for iTunes to change tags or artwork; none at all.

I didn't think I'd recommend that users not upgrade to a new version of iTunes, but this time I will. If you have a carefully curated music library, manually tagged, with painstakingly chosen or scanned album artwork, stay away from iTunes 12.2. Especially if you plan to use iTunes Match, Apple Music, or iCloud Music Library.

If, however, you don't have much music, it probably won't affect you. You might find that iTunes 12.2, with Apple Music, is just fine. It's probably fine for a lot of people, but it's toxic for music libraries that have been maintained with care.

Apple, you've let me down.