Happy New Year. May it be great for you as well.
Shoulder surgery! Something I would dread as a Rock Climber, particularly as I have a bit of a weakness in one shoulder, so I feel the risk of injury!
The naming of some functions in MC is unfortunate, as there are several very similarly named functions that do completely different things. Probably because of the style of progressive development JRiver uses, and the desire not to rename old functions.
I have set the Id Server to require Authentication (user/password), but the controls indicate "Read-only Authentication: Username and Password" and the drop-down lists "Username and password." Is that correct? Or should it read "Disabled" so that it can Read AND WRITE?
"Read-only Authentication" should be set to "Disabled".The first "Authentication" setting provides Read/Write access to the MC Server Library. It must be ticked on, and have a Username and Password set.
The second "Read-only Authentication" setting provides Read-Only access to the MC Server Library. If it is set to "Everyone", then it seems from previous discussions that MC Clients are forced into using a Read-Only connection, because the user on the MC Client isn't asked for the Read/Write Username and Password. So everyone just gets Read-Only access. If it is set to "Username and Password", and the first "Authentication" setting is ticked on, I suspect that the MC Client still connects in Read-Only mode. Certainly if the same Username and Password are used in both, MC would probably give priority to a Read-Only connection. If a different Username and Password were used for each setting I guess that MC would pick the type of connection based on which Username and Password were provided by the user. But it gets a little messy after the first ever connection, because the MC Client remembers the Username and Password it used last time, and hence gets the connection type it used last time. So disable that second setting.
Now, here's a big question: My understanding is that the Win10 Client should READ the Id. But you're using the word "Sync."
A MC Client receives a full copy of the MC Server Library when it connects. In that respect, I guess it "reads" the Server Library, but only on connection each time the Client connects. After that, if changes are made on the MC Client, including just playing files which increases the play count, for example, those changes are synchronised back to the MC Server Library. A MC Client doesn't actively read from and write to the MC Server once it is connected. It is sort of an arms-length relationship.
MC will automatically sync changes on the Client back to the Server if the settings at "Options > Media Network > Client Options (when connected to a Library Server) > Auto sync with server" is ticked
on the MC Client. This is not a Server setting, but a Client setting. If you have this setting turned on, you don't need to use the "Sync Changes with Library Server" function, as long as you allow MC time to complete the synchonisation of new data back to the Server, before closing the Client, as explained in my previous post.
I'm using the File, Library, Sync Library command from the Client
Don't use that. Ever. It is a completely different function. It is designed to sync both the MC Server Library and the media files to a local PC, which is what you are seeing it doing. I have also found it a little inconsistent in some testing I did. But regardless, it isn't what you want. That "Sync Library" command shouldn't even be active if you are connected to a MC Server Library. It should be greyed out. So if you are able to run that, you aren't connected to the MC Server Library on the Id.
The "Sync Changes with Library Server" function that I referred to is one of the buttons visible when you are connected to a Library Server and select "Playing Now > Playing from {your library server name} > {your library server name}". See the first image.
The function is also available under "File > Library > Sync Changes with Library Server". See the second image. Also note in that image that the "Sync Library" menu function is greyed out, as I am connected to a Server.