Virtual Machine Folder ACL access denied

I upgraded a Windows 2008 Hyper-V server to R2 and one of the virtual machine failed to start with error “Account does not have sufficient priviledge to open attachment “<Virtual machine file>” (0x80070005). (Virtual machine ID <GUID>)”.

Hyper-V could not read the virtual machine files due to ACL issues. Added SYSTEM account, etc does not work as Hyper-V has it’s own Service SID “NT VIRTUAL MACHINE”

To resolve this, try the follow:

Open the directory that stores your virtual machine

Open the “Virtual Machines” subdirectory under your virtual machine directory

Record the GUID as per the file name of the .xml file in this directory

Run icacls “<virtualmachinefolder>” /grant “NT VIRTUAL MACHINE\<virtualmachineguid>”:F /T