iTunes Match silently replaced original rips with 256 kbps AAC. Audit what's actually in your library and rebuild from the originals you still have.
iTunes Match (the iCloud-based service that ran from 2011 to its quiet retirement) had a side effect many users discovered too late: when iTunes Match "matched" your file to a track in its catalog, it replaced your high-quality local file with the iTunes catalog's 256 kbps AAC version on next sync. Original CD rips, lossless tracks, even hand-curated FLACs got silently downgraded. Now, years later, audiophile collectors find their iTunes Media folder full of 256 kbps AACs and wonder where their lossless library went.
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iTunes Match's silent file replacement is one of the cleanest case studies for why audiophile library audits matter — the damage was invisible at the time and only surfaces years later when you go looking for the original lossless files. MLD's role isn't to undo iTunes Match (that's not possible — the files are gone on machines that synced) but to help you find what survived, identify the downgraded files for replacement, and build a clean library going forward. The local-only operation means your library audit never reveals more to iCloud than was already there.
No. The original files were replaced locally during sync. They're recoverable only from backups (Time Machine, manual copies, secondary drives) that pre-date the iTunes Match sync. MLD helps you find those originals on backup drives and pull them into a clean library.
Modern Apple Music downloads are genuinely lossless (when you've selected lossless quality) and don't replace your local files. The iTunes Match silent-replace problem was specific to the older Match-mode behavior. New Apple Music subscribers don't have this issue.
The quality score distribution tells most of the story. A cluster at the AAC 256 kbps quality level (typically 60–75) where you expected lossless content (90+) is the smoking gun. Cross-check against backups to identify specific tracks.
Apple Music's local cache for offline listening lives in a separate location from your library — `~/Library/Group Containers/group.com.apple.AppleMusic/...` on Mac. Those files are managed by Apple Music itself and aren't audited by MLD as part of your library.
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