>>If you just want to make sure your application isn't going to run out of free space, then you really only care about the volume(s) to which you have been granted access. If these are mounted on your local computer as SMB/CIFS volumes, then they should respond to DOS, Win32 or .Net calls to get information about them. Googling I find http://msdn.microsoft.com/en-us/library/system.io.driveinfo%28v=vs.110%29.aspx?cs-save-lang=1&cs-lang=vb#code-snippet-1 . The .TotalSize, .TotalFreeSpace and (especially) .AvailableFreeSpace properties should give you what you need.
>
>This is good if you have a map drive. Because, this requires a map letter. If you try to use \\NAS\ShareName, this will give:
>
>"Object must be a root directory ("C:\") or a drive letter ("C")."
>
>This is why I was not able to use that approach on the VM.

How about http://stackoverflow.com/questions/14465187/get-available-disk-free-space-for-a-given-path-on-windows ?