I have stored an mp3 in my OneDrive music folder on my Win 10 (build 14393.693) and it syncs to OneDrive online. So far so good. When I go to https://music.microsoft.com
it is not there. When I click on the song on https://onedrive.live.com/ it starts to open music.microsoft.com and I see:
So something is wrong there:
So I cannot play the mp3 which is in my OneDrive music folder. They appear up on onedrive.com so the onedrive sync is working fine. The problem is with my groove connection. When I locally start groove, there is the mp3. Because I stored it on my HDD it loads locally, but does not show up from onedrive.
Local Groove:
I clicked on the option to reset my groove catalog which seems to reset my cloud collection:
This does give me my recently added track. But only as “unknown”
There is a lot which is not known…
Perhaps this all happened because I added the onedrive/music folder which is local as folder to watch for groove:
I have removed that reference now and this seems to fix it 
Even the new track is not an unknown one!
I hope this might help someone