Has all the music saved in Your Library disappeared? If so, there could be a couple of explanations for this.
There’s a chance that you could be logged in to another account, which doesn’t have the same music saved in Your Library. To check for other accounts, use the steps in this article.
If you think this has happened because someone’s gained access to your account, you should follow the steps in this article closely.
If you’re definitely logged in to the correct account but still can’t see the music saved in Your Library, it’s not possible to get your tracks back. You’ll need to find them in the app and save them again.
We’d also suggest trying a clean reinstall to see if this makes the saved music reappear.