Diskpart to extend system C drive in Windows Server 2008

Updated on: July 11, 2019

This article introduces how to extend C drive with diskpart in Windows Server 2008 R2, and the limitations to extend system partition with diskpart command.

Cannot extend C drive with diskpart by shrinking

Diskpart is a command line tool and many server administrator like to use such kind of tools. It has many commands to manage disk partitions. The extend command can be used to expand system partition and data volumes without losing data. However, it works under very restricted condition.

Many people encounter issue while extending partition with diskpart command on Windows 2008 server, the common error is The size of the extent is less than the minimum. Then why cannot extend C drive with diskpart?

Firstly, you should know that before extending a volume there must be free Unallocated space. If you did not delete or shrink other volume to get such space, of course you cannot extend partition with diskpart command or other tools.

The problem is, you cannot extend C drive with diskpart after shrinking D or other volumes.

Unable with diskpart

As you see in the screenshot, diskpart cannot extend system partition C after shrinking the contiguous drive D.

This is because:

Diskpart can only extend NTFS partition when there is adjacent Unallocated space on the right.

After shrinking D: drive, Unallocated space is on its right side. Therefore, to system partition C, this Unallocated space is nonadjacent.

Diskpart also cannot extend Unallocated space to the right partition E.

How to extend system partition with diskpart

To extend C: drive with diskpart in Windows Server 2008 (R2), the only way is by deleting the right contiguous partition.

Diskpart works

As you see in the screenshot, diskpart successfully extend C drive after I deleting D.

If you installed programs or any Windows services to D: drive, you cannot delete it to get right adjacent Unallocated space, in that case, diskpart cannot help you extend system C: drive.

Steps to extend system C: drive with diskpart in Windows Server 2008 if you can delete D:

  1. Press Windows and R together on keyboard, type diskpart and press Enter.
  2. Type list volume and press Enter.
  3. Type select volume C and press Enter.
  4. Type extend and press Enter.

Better tool and method to extend system volume

Comparing with diskpart, NIUBI Partition Editor is much more powerful, it is able to:

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

Video guide