Why would I be able to access files on a VM from CMD but not File Explorer?

I have had a problem going back I think all the way to when I installed Workstation 10...

I can access shares on my host Windows 8.1 system via Windows networking from inside a Windows 8.1 VM no problem.  And I can access the shares in the VM from my host via a CMD window, but I cannot access the VM from the host via File Explorer:

Why?

-Noel