I tried to add a Windows 10 shared drive to Volumio today, something I have done a few times before for testing. I was surprised that if failed and investigation showed I was getting a message the ‘Host is Down’. Further investigation revealed the culprit - a recent Windows Update (Pro Insider) included a change that required me to add vers=3.0 to mount a share that was previously working without it.
Simply add ‘vers=3.0’ to the ‘Options’ box under ‘Show Advanced Options’ in Volumio settings.
Hope that helps someone.