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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. Changing my metadata or changing my artwork is a violation of my music library. I’ve ripped a few thousand CDs, tagged them very carefully, and added artwork to every track in my iTunes library. On your phone, head to Settings, then General. For iOS 11, it’s going to be 12.6.3.6 or later.
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This is a known-to-Apple issue, and it will. When encountered, a duplicate of a purchased song will (almost always) cause iTunes to silently stop syncing.
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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. For instance, if you are running a version of iOS 10, then you need iTunes 12.5.1.26. In the end, the problem turned out to be as simplebut as deadlyas this: In the current version of iTunes/iOS, theres a bug that only appears when you have duplicates of purchased songs. 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. 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. 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. But I won’t upgrade my iMac, which is where my large music library (around 65,000 tracks) is stored.
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It has a small iTunes library, which, together with my iTunes Store purchases, comes to about 9000 tracks.
#Itunes 12.5.1 syncing problem update
I did update iTunes on my MacBook Pro my test computer.
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