Serenity Caldwell, writing for iMore:

On Wednesday, I saw a post widely shared about an unfortunate individual who lost half of their local library and was blaming Apple Music for automatically deleting their local files.

I sympathize, and I’m very glad this person had a backup of their music, but I want to dispel some FUD here: Apple Music has definite problems and its matching algorithms aren’t great, but this is simply not how the service works. Apple Music should never automatically delete files off your Mac’s hard drive unless you specifically delete them first.

Serenity does a terrific job explaining this mess. In a nutshell, back up your original music library and do what you can to never delete music from it. If you need more space, get a bigger drive. If you must delete some music to save space, you are risking going down the rabbit hole of doom, so make sure your backup is complete and dependable.

I sure hope Apple addresses this.