What is the maximum size for a VHD?
The maximum size for a VHD is 2 Terrabytes.
You can find more information on the Microsoft Technet Page, VHD:
The maximum size for a virtual hard disk is 2,040 gigabytes (GB).
However, any virtual hard disk attached to the IDE controller cannot exceed 127 gigabytes (GB). To support a larger virtual hard disk size, attach the virtual hard disk to a SCSI adapter.
Wherever possible, you should use SCSI as they are faster. You can also convert a virtual IDE disk to SCSI disk.