I just went with the manual method of hitting "Sync Changes with Library Server."
This should work.
Are you saying that none of the tagging is retained, or just certain fields?
I know the QNAP Nas server version of JRiver is recent and could still have some issues .. I don't have one to try. But when you say your Mac installation and loading the library on the NAS makes me think like you were running a JRiver set-up from your MAC and then changed the config to install JRiver on the QNAP which is now running as the media server?
I'd check to see that the MAC is not running media server, and is only configured as a client. You main library is now on the QNAP, it probably should be configured to autoload media server. As the NAS is probably always on, the main library is always going to be loaded. But the client, your MAC, has to be set-up so it is loading the QNAP library. Running two version of media server can be "confusing" to the network sometimes. If by chance you are loading a local library on your MAC of course its not going to sync with the server. Does this make sense?
Remember that moving the library refers to the JR database, not the media files (semantics
)
Maybe I'm off the mark here, but I'd double check that your MAC is indeed loading the QNAPs library and is acting only as a client in Network Options.
Now maybe you aren't talking about this but that it is not writing the tags to music files themselves (but the changes are still visible in JRIver like Bob asked you). If that's what you mean check that the fields in question are marked to "Write to the file when possible" in options Manage Library Fields and that read/write permissions are ok for the shared drives on the QNAP.