What OS are you using? Do you see your VHD mounted in Explorer? When I tested this with Windows 10 1703, I get the same output in the console (Attached = False), but when I check Explorer, I see the mounted VHD with a drive letter.
yes I am running 17.03 as well. I see it in Disk Management mounted but there is no drive letter assigned to it. I can assign a drive letter to it from DiskPart and from Disk Management but not from PowerShell as it it doesn't even return a ID for the disk number so I can't pipe it to the Get-Disk cmdlet