Diskpart extend volume in Windows Server 2008

Updated on: November 16, 2019

This article introduces how to extend partition with diskpart in Windows Server 2008 R2. Extend system partition C or drive D via diskpart command line prompt.

How to extend partition with diskpart in Server 2008

Diskpart is a native command line tool integrated from Windows XP, it has similar functions with Disk Management but work via command prompt. Comparing with GUI Disk Management, Diskpart is faster and easier if you know disk partition structure and other information clearly, otherwise, you may be confused.

Diskpart only displays single partitions with part of parameters, furthermore, it doesn't display Unallocated space which is required while extending a partition. To better understand how Diskpart works to extend volume, I attached the screenshot of Disk Management as comparison.

Steps to extend volume with diskpart in Windows Server 2008:

Step 1: Press Windows and R together on keyboard, type diskpart and press Enter, then diskpart command prompt will be opened.

Step 2: Type list volume and press Enter in the command prompt window, then you'll see all partitions in a list.

Open diskpart

In Server 2008 Disk Management, you'll see more information of single partitions on the top and disk with partition structure on the bottom.

Disk Management

Step 3: Type select volume C and press Enter. C is drive letter or number of the volume that you want to extend. Before any operations to a disk partition, you must select and give focus to it.

Step 4: Type extend and press Enter. If you want to specify an amount, type extend size= (in MB).

Partition extended

Diskpart report successfully extended this volume, you'll see the result visually in Disk Management.

Volume extended

If your disk partition configuration meet the requirements, it is very easy and fast to extend partition with Diskpart in Windows Server 2008. But in most cases, diskpart cannot help you extend disk partitions.

Limitation to extend volume with diskpart command

Type help extend in diskpart command prompt, you'll see how Extend works, the syntax and the limitations.

Extend command limitation

There are 3 common restrictions in basic disk:

When I repeat to extend D: drive with diskpart, I receive error - The volume cannot be extended because the file system does not support it.

Extend error

Drive D is formatted with FAT32, which is not supported, so Extend Volume is disabled in Disk Management, too.

Extend Volume disabled

I have combined the 10GB adjacent Unallocated space to C drive with diskpart before, when I repeat without such space, I receive error - There is not enough usable free space on specified disk to extend volume. Disk Management is also grayed out for C: drive.

Diskpart error

Extend Volume greyed


To extend partition with diskpart command in Windows Server 2008, you must delete the right contiguous partition first. In addition, the partition that you want to expand must be NTFS.

If there are programs or any Windows services running from drive D, you cannot delete it, therefore, diskpart cannot extend system partition C. If you want to extend volume D, there must be another volume on its right side, furthermore, there must be other partition or disk to transfer files.

Better way to expand volume with partition editor

With server partition manager, there are no such restrictions. You just need to drag and drop on the disk map, shrink a drive and make Unallocated space on either side, this space can be combine to any contiguous or nonadjacent partition in the same disk.

Download NIUBI Partition Editor and follow the steps in the video to extend volume in Windows Server 2008:

Video guide

The rules: right click any NTFS or FAT32 partition and select "Resize/Move Volume" from the list, drag the border towards the other side in the pop-up window, then you can shrink this partition or extend this partition by merging contiguous Unallocated space. Drag the middle position towards other side, then you can move this partition and associated Unallocated space.

Besides shrinking, moving and extending partition, NIUBI Partition Editor helps do many other disk and partition management operations.