I have that ticked off on all my units NO FILES are transferred between them only the library but then all my files are located on a shared NAS available on the network.
I do not understand the setup are you using. Why do you want all your data to be located on each machine? Perhaps to use your machine and the system outside your network? The Auto Sync option is for a client that is connected to a server meaning that you have a server hosting the library in your system. The WIKI
https://wiki.jriver.com/index.php/Library_Server_Sync states as follows:
What Is Synced- File value changes (artists, keywords, playback statistics, etc.)
- File deletes
- File adds (server adds always go to clients, client adds go to server if the server can reach the file)
- Playlist creation, management, and deletion
- Playlist changes
- Television recording schedule
Library and File Tools
Missing from that list is the impact on Library Tools, the Locate > On Disk, and Send To > External Menu items. Generally, these tools that "touch the disk" only work from the Client side if you have direct filesystem access to the files from the client-side (the full path of the files must match the path on the Server-side).
Typically, this means to access these tools you need to map a network drive to your media volume, and give it the same letter as it has on your server. If this is inconvenient, you can also do this by importing the files on the server-side as a UNC path rather than a "drive letter based path". (The server will work just as happily on files imported via UNC shares even if they're "really" locally accessible on the server. And then the path will always match what the client sees so long as you're on the same LAN and the computer account has access to the share.)
A notable exception to this general rule is the Rename, Move, and Copy Files Tool, which doesn't work at all from the client-side, even if you do have your file paths set up right and all locally accessible.
Important: Mapping a network drive (or sharing the files via the OS) is not required for playback or for all of the functions supported by the Library Sync system (including tagging). This is only required if you want to be able to access these additional toolThe WIKI states that deleted files and added files will be synced. It is not clear to me if this means a physical sync as you require or simply the library representation. Perhaps someone from J River can explain further!
My set up is different so I am not able to enlighten more on this topic. When I use portable devices )without network access) I have a special contents list that I sync to the portable through the dedicated system for such sync provided by MC (Drives and Devices).
When I use a portable with network access I use the Server client system and stream the content over the network. I.e a mobile phone
Rgrds ../O