Yes just as mwillems said .. authentication and sync
Just to add my 2cents though if you are doing a lot of tagging in one sitting (or you are spending a bunch of time on a particular album ... looking up soloists etc changing date tags for box sets while listening to it)
I really recommend turning OFF the auto-sync option ... but
only temporarily. Keep it on as a default though. Every so often manually "sync changes with Library server" (under File=>Library from the top menu). When you are finished, remember to check the option back to "on". The danger of this is that if you forget to manually sync with the auto sync off and you close the client pc down all your work will be gone. It does not sync every time you make a change. You are not actually writing to the sever library directly (actually I'd be curious as to what actually triggers the autosync if anybody can tell me). But you control when and what gets synced this way.
I know that some people think this option to manually sync is only for very specific reasons, but I have lost too much of my changes due to the server autosyncing the servers info (the old stuff) over the new or I (or my network) shut down the client before the "auto-sync" actually happened.
When just tagging some genres of pop/rock albums or play stats just the autosync is fine and you don't forget to sync that way of course
Anyways I'm a
bit absolutely OCD with my tagging and you might not need to force a manual sync ... just thought I'd share what I do
as mwillems said this will work for just about any metadata modification. For cover art and path changes, file renaming redoing views and things, I like TeamViewer, much better than windows pro remote desktop and easy to set up too, but I always tag directly from the client PC.