Recovering plex library from backup: 1. Stop Plex Media Server. 2. Rename current database. com.plexapp.plugins.library.db -> com.plexapp.plugins.library.db.bak 3. Rename last DB snapshot to com.plexapp.plugins.library.db. So com.plexapp.plugins.library.db-2020-10-05 -> com.plexapp.plugins.library.db 4. Restart PMS Path to database is: /Plex/db/Library/Application Support/Plex Media Server/Plug-in Support/Databases