Just to add a bit more information to the above to explain what I am trying to do. The layout of the disk is presently: -
1. C: Windows 7 Primary 30.01GB NTFS
2. Unallocated 208.38GB
3. Primary (not yet used) 25.0GB NTFS
4. Unallocated 208.37GB NTFS
I wish to make the whole of item 4 an Extended Partition,using the following in DiskPart: -
Create partition extended offset=???
and then to create a Logical Partition within it,
(leaving out the Size parameter should result in all the unallocated space being encompassed in the Extended Partition).
I have tried various calculations of the Offset parameter but all have resulted in DiskPart issuing a message "Virtual Disk Service error. There is not enough space for this operation."
Can someone tell me what I am doing wrong and give me the correct method for creating the Extended Partition. I don't understand why the message is referring to 'Virtual' because I am dealing with a 'physical' disk.