Deleting your Library.json
Sometimes it might be necessary for you to delete your Library.json file.
This file holds a list of your installed content, but does not actually contain the content itself. That makes it safe to delete when there are display issues, or there are download issues, allowing you to re-import your existing content.
Still - you should only do this if you are sure what you are doing, or have been asked by OT Support to do so.
Locating the Library.json
The Library.json is in your Sampler Data folder. You can find it at:
Windows: C:\Users\<USERNAME>\AppData\Local\Orchestral Tools\SINE Player
macOS: <SystemDrive>:Users:<Username>:Library:Application Support:Orchestral Tools:SINE Player
Just delete the Library.json - it will be re-created when you open SINE again. You can re-import existing content using +Collection in the Library View.