I have lost access to a volume/partition on Hyper-V although the Vm runs the VHDX file

Question

I have a partition on one of my drives that I am unable to access as administrator. I am running Hyper-V 2012 R2. If I try to select the drive at the command prompt I receive Access Denied. In diskpart the Volume and drive letter are shown but the Drive
label is not (this must be a clue). Diskpart: when the volume is selected and detail volume is entered it returns details but gives a warning "Diskpart has encountered an error: Access is denied See the system Event log for more information". The
system log has no useful information other than "
Volume G: (\Device\HarddiskVolume2) is healthy.  No action is needed."
Resetting attributes in diskpart, i.e. attr vol clear readonly hidden returns completed OK.
Takeown /F G: suggests that it completes OK, but icacls fails with Access denied when used to either check permissions or alter them. I am at a loss to work out how to get access to my VHDX files so that I can back them up and move to another Server. If
I try and export my VM the process fails with access denied when the copy process starts.
Thank you to anyone who can help me, and those who are reading this.

Answer 1

I have used an answer by Tony Britten to achieve my required aim.
http://social.technet.microsoft.com/Forums/en-US/87679d43-04d5-4894-b35b-f37a6f5558cb/solved-how-to-take-ownership-and-change-permissions-for-blocked-files-and-folders-in-powershell?forum=winserverpowershell It used Powershell and Tony's own answer using
a 3rd party module PSCX. Thank you Tony