User 'X\y' failed to create external configuration store at 'D:\Hyper-V':

I have a Hyper-V server which has served me well, so far. It's been in a workgroup until recently, and has hosted four machines. I hadn't used it for a while and decided to join it to my new domain. I also had to apply a load of patches.

Now, I'm trying to create a new machine. I've already created the hard disk and when I try to create the VM I'm getting a window which says:

The server encountered an error while creating DomainSql1.

The operation failed.

Failed to create external configuration store at 'D:\Hyper-V': General access denied error (Virtual machine ID 0x80070005)

and in the event log:

Log Name: Microsoft-Windows-Hyper-V-VMMS-Admin

Source: Microsoft-Windows-Hyper-V-VMMS

Date: 22/07/2012 06:53:09

Event ID: 13000

Task Category: None

Level: Error

Keywords:

User: SYSTEM

Computer: Computer.Domain.local

Description: User 'DOMAIN\Administrator' failed to create external configuration store at 'D:\Hyper-V': General access denied error (Virtual machine ID 0x80070005)

I've had a search and found one problem which mentions symbolic links but that doesn't seem to apply to me as I can see the symbolic link in "C:\ProgramData\Microsoft\Windows\Hyper-V\Virtual Machines" and the folder path its pointing to get created at "D:\Hyper-V Domain\DomainSQL1\Virtual Machines" but it's empty - no XML file is created. The Virtual Machines identity has the following permissions on the Virtual Machines folder:

• List folder/read data
• Read attributes
• Read extended attributes
• Create files/wroi