Private Declare Function OpenVirtualDisk Lib "VirtDisk" (ByRef VirtualStorageType As PVirtualStorageType, ByVal Path As String, ByVal VirtualDiskAccessMask As Long, ByVal Flags As Long, ByVal Parameters As Long, ByVal Handle As Long) As Long
Private Type GUID
 Data1 As Long
 Data2 As Integer
 Data3 As Integer
 Data4(7) As Byte
End Type
Private Type PVirtualStorageType
   DeviceId As Long
   VendorId As GUID
End Type
Const VIRTUAL_STORAGE_TYPE_DEVICE_UNKNOWN = 0
Const VIRTUAL_STORAGE_TYPE_DEVICE_ISO = 1
Const VIRTUAL_STORAGE_TYPE_DEVICE_VHD = 2
Const VIRTUAL_STORAGE_TYPE_DEVICE_VHDX = 3

  Const VIRTUAL_DISK_ACCESS_NONE = &H0
  Const VIRTUAL_DISK_ACCESS_ATTACH_RO = &H10000
  Const VIRTUAL_DISK_ACCESS_ATTACH_RW = &H20000
  Const VIRTUAL_DISK_ACCESS_DETACH = &H40000
  Const VIRTUAL_DISK_ACCESS_GET_INFO = &H80000
  Const VIRTUAL_DISK_ACCESS_CREATE = &H100000
  Const VIRTUAL_DISK_ACCESS_METAOPS = &H200000
  Const VIRTUAL_DISK_ACCESS_READ = &HD0000
  Const VIRTUAL_DISK_ACCESS_ALL = &H3F0000
  Const VIRTUAL_DISK_ACCESS_WRITABLE = &H320000
  
   Const OPEN_VIRTUAL_DISK_FLAG_NONE = &H0
  Const OPEN_VIRTUAL_DISK_FLAG_NO_PARENTS = &H1
  Const OPEN_VIRTUAL_DISK_FLAG_BLANK_FILE = &H2
  Const OPEN_VIRTUAL_DISK_FLAG_BOOT_DRIVE = &H4
  Const OPEN_VIRTUAL_DISK_FLAG_CACHED_IO = &H8
  Const OPEN_VIRTUAL_DISK_FLAG_CUSTOM_DIFF_CHAIN = &H10
Private Sub Form_Load()
Dim vst As PVirtualStorageType, hnd As Long
vst.DeviceId = VIRTUAL_STORAGE_TYPE_DEVICE_VHD
w = OpenVirtualDisk(vst, "E:\1.vhd", VIRTUAL_DISK_ACCESS_ATTACH_RW, OPEN_VIRTUAL_DISK_FLAG_CACHED_IO, 0&, hnd)

Public Declare Function OpenVirtualDisk Lib "VirtDisk" (VirtualStorageType As VIRTUAL_STORAGE_TYPE, _
        ByVal Path As Long, ByVal VirtualDiskAccessMask As VIRTUAL_DISK_ACCESS_MASK, ByVal Flags As OPEN_VIRTUAL_DISK_FLAG, ByVal Parameters As Long, Handle As Long) As Long

Public Type VIRTUAL_STORAGE_TYPE
   DeviceId As VirtualStorageDeviceType
   VendorId As GUID
End Type
Public Enum VirtualStorageDeviceType
    VIRTUAL_STORAGE_TYPE_DEVICE_UNKNOWN = 0
    VIRTUAL_STORAGE_TYPE_DEVICE_ISO = 1
    VIRTUAL_STORAGE_TYPE_DEVICE_VHD = 2
    VIRTUAL_STORAGE_TYPE_DEVICE_VHDX = 3
End Enum
Public Enum VIRTUAL_DISK_ACCESS_MASK
    VIRTUAL_DISK_ACCESS_NONE = &H0
    VIRTUAL_DISK_ACCESS_ATTACH_RO = &H10000
    VIRTUAL_DISK_ACCESS_ATTACH_RW = &H20000
    VIRTUAL_DISK_ACCESS_DETACH = &H40000
    VIRTUAL_DISK_ACCESS_GET_INFO = &H80000
    VIRTUAL_DISK_ACCESS_CREATE = &H100000
    VIRTUAL_DISK_ACCESS_METAOPS = &H200000
    VIRTUAL_DISK_ACCESS_READ = &HD0000
    VIRTUAL_DISK_ACCESS_ALL = &H3F0000
    VIRTUAL_DISK_ACCESS_WRITABLE = &H320000
End Enum
Public Enum OPEN_VIRTUAL_DISK_FLAG
    OPEN_VIRTUAL_DISK_FLAG_NONE = &H0
    OPEN_VIRTUAL_DISK_FLAG_NO_PARENTS = &H1
    OPEN_VIRTUAL_DISK_FLAG_BLANK_FILE = &H2
    OPEN_VIRTUAL_DISK_FLAG_BOOT_DRIVE = &H4
    OPEN_VIRTUAL_DISK_FLAG_CACHED_IO = &H8
    OPEN_VIRTUAL_DISK_FLAG_CUSTOM_DIFF_CHAIN = &H10
End Enum

Private Sub Command8_Click()
Dim tVST As VIRTUAL_STORAGE_TYPE
Dim hVHD As Long
Dim vhdhr As Long
tVST.DeviceId = VIRTUAL_STORAGE_TYPE_DEVICE_VHD

'VIRTUAL_STORAGE_TYPE_VENDOR_MICROSOFT
Call DEFINE_GUID(tVST.VendorId, &HEC984AEC, CInt(&HA0F9), CInt(&H47E9), &H90, &H1F, &H71, &H41, &H5A, &H66, &H34, &H5B)

vhdhr = OpenVirtualDisk(tVST, StrPtr("C:\util\test.vhd"), VIRTUAL_DISK_ACCESS_ALL, OPEN_VIRTUAL_DISK_FLAG_NONE, 0&, hVHD)

Debug.Print "vhd hr=0x" & Hex$(vhdhr)
MsgBox "h=" & hVHD

CloseHandle hnd
Exit Sub

Public Sub DEFINE_GUID(Name As GUID, L As Long, w1 As Integer, w2 As Integer, B0 As Byte, b1 As Byte, b2 As Byte, B3 As Byte, b4 As Byte, b5 As Byte, b6 As Byte, b7 As Byte)
  With Name
    .Data1 = L
    .Data2 = w1
    .Data3 = w2
    .Data4(0) = B0
    .Data4(1) = b1
    .Data4(2) = b2
    .Data4(3) = B3
    .Data4(4) = b4
    .Data4(5) = b5
    .Data4(6) = b6
    .Data4(7) = b7
  End With
End Sub