How to Extend C Drive? Diskpart vs Server Partition Software

February 14, 2019

How to extend c drive in Windows Server 2003, 2008, 2012? You can follow this guide to enlarge c drive via diskpart service and another versatile partition manager software.

The importance of extending c drive in server

Usually, c drive is the system partition either in PC or in server. If system partition is running out of space and measures are not carried out immediately, much inconvenience will be made to users. The most common problem due to low system space is slow reply of computers. At that moment, if you are making an important working file or downloading/uploading something, it may worry you like an ant on a hot pot. Therefore, it is of great importance to increase the capacity of c drive.

How to extend c drive in server using diskpart?

Diskpart is a Windows Server self-contained utility which deals with disks, partitions or volumes by running a command line through scripts or direct inputting commands. To enlarge drive c, briefly, you only need to input "list volume", "select volume c" and "extend" into diskpart command interpreter. However, there are still some parts need your attention. Therefore, following are the specific steps:

  • Step1. Click start and type "diskpart" in the column, then press Enter on the keyboard.
  • Step2. Type "list volume" and press Enter on the keyboard to display the existing volumes on the computer.
  • Step3. Type "select volume c" and press Enter on the keyboard to focus on volume c.
  • Step4. Type "extend [size=n] [disk=n] [noerr]" to extend volume c to disk n of size n.

Like this, Partition c has been extended with the unallocated space successfully.


  • Contents in the square brackets are unnecessary. That is to say, you can only type "extend" to extend the size of the selected volume.
  • "size=n " specifies the space, in megabytes (MB), to add to the current partition. If you do not specify a size, the disk is extended to use all the next contiguous unallocated space.
  • "disk=n " determines the dynamic disk on which to extend the volume. Space equal to n is allocated on the disk. If no disk is specified, the volume is extended on the current disk.
  • "noerr" is for scripting only. When an error is thrown, this parameter specifies that Diskpart continue to process commands as if the error did not occur. Without the noerr parameter, an error causes Diskpart to exit with an error code.
  • If there is no unallocated space behind c drive, you cannot extend it. In order to extend it, you must make some unallocated space and put it behind volume c.

AOMEI Partition Assistant Server extend server drive c

AOMEI Partition Assistant Server is an software which is custom for Windows Server disk management, whether it is server 2003, 2008 or 2012 R2. To know how to enlarge partition c drive, please follow the steps bellow.

Step1. Download, launch and run partition assistant. Immediately, in the main page of partition assistant, you can see how many disks you have in your server and their details, such as file system type, capacity, used space and free space.

Step2.Usually, there is no unallocated space right behind c volume, so you have to make some by resizing the partition that is right behind c drive. To do this, you just need to right click the partition, choose resize partition and pull the bar on the left end rightward in the pop-out window. After applying it, some unallocated space will exist right next to disk c. If you pull the bar from the right end leftward, the unallocated space produced will exist on the very right of the partition you operate on instead of c drive.

Resize A Partition

Note: If the partition behind c disk is also almost out of space, you have to shrink another partition to get unallocated room. Then, you can move the new-produced unallocated space to the right of c drive.

Move And Resize Partition

Step3. Step3. Right-click partition c, choose resize partition and pull the bar rightward. Then, apply it.

Extend Partition Size

Comparison of the two ways above to extend c drive

Disadvantages of making use of Diskpart to extend c volume in Server:

  • C partition can only be extended by running Diskpart from a command line by bootable CD.
  • It is very difficult for many users to use command line.
  • Data loss may be caused by inputting incorrect orders and the orders cannot be repealed.
  • Only when you get some unallocated space behind the c volume, you can extend the c drive.
  • It stops the Server from running for a long time.

Though Partition Assistant still need unallocated space very behind c drive before it can enlarge the c partition and data might also lose when you take some wrong operations, it is very easy for you to use and it runs really fast. Except the functions above, there are still many provided by partition assistant, such as merge partitions, split partition and format partition.