windows – VirtualBox Error: “Could not get the storage format of the medium (VERR_NOT_SUPPORTED)” for Disk2VHD .VHD File

I’m trying to use a .VHD file created with Disk2VHD in VirtualBox, but when I try to attach it, I get the following error:

Could not get the storage format of the medium 
'C:\Users\stirba\Desktop\NBCEDTEST2.VHD' (VERR_NOT_SUPPORTED).

 Codice uscita: VBOX_E_IPRT_ERROR (0X80BB0005)
 Componente: MediumWrap
 Interfaccia: IMedium {ad47ad09-787b-44ab-b343-a082a3f2dfb1}
 Chiamante: IVirtualBox {7682d5eb-f00e-44f1-8ca2-99d08b1cd607}
 RC chiamante: VBOX_E_OBJECT_NOT_FOUND (0X80BB0001)

Question:
Why is VirtualBox not recognizing my .VHD file?
Is there a way to fix or convert the Disk2VHD image properly for VirtualBox?
Do I need to modify the .VHD in any specific way to make it compatible?
Any help would be greatly appreciated!