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Attach a virtual hard disk (VHD) from external USB storage in Windows 8 Hyper-V

Author by Steve Borgwardt

For our development environment we use a lot of virtual machines depending upon the platform or project we are working on.  I have been storing the majority of these virtual hard disks (VHD) files on my external USB drive due to the large capacity (2TB) of it while using Windows Server 2008 R2 as my host OS.

After recently upgrading to Windows 8 Pro and enabling the Hyper-V manager I created a new VM and attached the VHD from my external USB drive and received a strange error message:

Error applying Hard Drive changes Failed to add device 'Virtual Hard Disk' Hyper-V Virtual Machine Management service Account does not have permission to open attachment. Error: 'General access denied error' (0x80070005)

At first this was strange, as I am the local Administrator on my host PC and I know for a fact I have permission to modify any files on my external USB hard drive.

After several hours of doing some searches and trying different permission settings I came across this forum on Technet about the issue and it appears while Microsoft is preparing a hotfix for this issue (as of February 2013), one reader appears to have found the solution.

Here are the steps in Windows 8 to fix this issue and allow the use of VHD files from an external USB storage device:

  1. Search for “Group Policy” under “Settings” to launch the Local Group Policy Editor found in Administrative tools.
  2. Under “Computer Configuration” expand, Windows Settings -> Security Settings -> Advanced Audit Policy Configuration -> System Audit Policies – Local Group and click on the “Object Access” category.
  3. Double-click “Audit Removable Storage” subcategory to open the properties window and click the checkbox for “Configure the following audit events” and leave the Success and Failure checkboxes unchecked. (This will change the audit event to “No Auditing”, versus “Not Configured”)
  4. Click OK and then reboot your PC.

Local Group Policy Editor

Audit Removable Storage

You should now be able to create a VM and attach a VHD file from an external USB storage device without receiving the permission error.


Steve Borgwardt

Senior Application Developer