How to extend C: drive in Windows Server 2012

by Lance, Updated on: December 4, 2020

This article introduces how to extend C: drive in Windows Server 2012 R2 without losing data. 4 ways to enlarge C drive partition with detailed steps.

It can't be better if you can extend system C: drive when it is getting full, nobody likes to waste a long time to recreate partitions and restore everything from backup. With right tool, you can add more free space to C: drive from another volume or disk. To extend C drive partition in Server 2012 R2, there are two kinds of tools: Windows native Diskpart command or Disk Management and third party partition editor software. In this article, I'll introduce full solution to extend C drive in Windows Server 2012 with detailed steps, select corresponding method according to your own disk partition configuration.

1. How to extend C drive with Server 2012 diskpart cmd

Both DiskPart and Disk Management are built in Windows Server 2012 (and R2), they are safe and easy, but on the other hand they only work under restricted condition. Diskpart work via command prompt, Disk Management work with graphical dialog box.

With either native tool, you must delete the right contiguous partition in advance before expanding C: drive.

Steps to extend C: drive in Windows Server 2012 with Diskpart cmd:

  1. Press Windows and R together on your keyboard, type diskpart and press Enter.
  2. Input list volume and press Enter in diskpart command prompt window, then you'll see all single partitions in a list.
  3. Input select volume D and press Enter to give focus to D drive. (D is the contiguous volume on the right of C drive.)
  4. Input delete volume and press Enter, the the disk space will be changed to Unallocated.
  5. Input select volume C and press Enter to give focus to C.
  6. Input extend and press Enter.

Diskpart extend

If you shrink D to expand C drive, you'll receive error - The size of the extend is less than minimum.

Extend error

2. Expand C drive in Windows Server 2012 Disk Management

Disk Management has graphic interface, so it's more user friendly than diskpart command. However, as I said above, you must delete D: drive before expanding C. This is because:

Therefore, if you want to extend C drive in Server 2012 (R2) without any software, you must delete D to get adjacent Unallocated space.

One more point, D drive must be Primary partition, otherwise, Extend Volume still greyed out for C drive after deleting D. Learn why cannot extend C drive in Server 2012 Disk Management.

Extend volume disabled

How to extend C drive in Server 2012 R2 Disk Management:

  1. Press Windows and X keys together and click Disk Management in the list.
  2. Right click D drive and select "Delete Volume".
  3. Right click C drive and select "Extend Volume", then simply click Next in pop-up dialog boxes.

Make sure there are no programs or Windows services installed in D drive. If you can delete it, remember to transfer files in advance.

3. How to extend C drive partition with free space in D or E

With server partition software, you can shrink drive D or any other volume on the same disk, and then add Unallocated space to C drive. Better than Windows native tools, third party software can make Unallocated space on either left or right when shrinking partition, and extend Unallocated space to either contiguous or non adjacent partition on the same disk. In this way, Operating System, programs and associated settings, as well as anything else keep the same with before.

However, there's potential data loss risk, you'd better back up in advance and run safe partition software. Better than other tools, NIUBI Partition Editor has Virtual Mode, Cancel-at-well and 1 Second Rollback technologies to protect your system and data. In addition, the advance file-moving algorithm helps resize partition 30% to 300% faster.

Download this program and you'll see the main window with disk partition layout and detailed information of each volume.

NIUBI Partition Editor

How to extend C drive in Windows Server 2012 R2 with NIUBI:

  1. Right click D: drive and select "Resize/Move Volume", drag left border towards right in the pop-up window, then part of free space will be changed to Unallocated on the left.
  2. Right click C: drive and select "Resize/Move Volume" again, drag right border towards right to combine this Unallocated space.
  3. Click Apply on the top left to take effect, done.

If you already shrunk D drive with Disk Management, or if you want to get free space from the non adjacent partition E. You should move Unallocated space behind C drive before expanding.

Watch the video guide how to enlarge C drive in Windows 2012 server step by step.

Video guide

If you use any types of hardware RAID array such as RAID 1/5/6/10, do not break array or do any operations to raid controller, simply follow the step above.

4. How to enlarge Server 2012 C drive with another disk

In some servers, there's only C drive on the system disk, in some other servers, there are several partitions but all of them are getting full. In these cases, no software can add space to C drive from another separate disk. To solve this problem, you have 2 choices.

Copy disk to a larger one and expand C drive with extra disk space.

Video guide

Move a partition to another disk, then delete it and add its space to C drive.

Video guide

How to extend C drive in Server 2012 VM in VMware/Hyper-V

Nowadays, virtual machines are widely used. If you run Windows 2012 as guest server in VMware/Hyper-V/Virtualbox, first of all, check there's available free space in another volume on the same disk. If yes, simply follow the steps above and there's no difference. If the entire virtual disk is full, you can expand it without copying to a larger one.

To extend C drive partition in Windows Server 2012/2016/2019/2003/2008, select one of the methods according to your own disk partition configuration. Besides shrinking, moving and extending partition, NIUBI Partition Editor helps you do many other disk partition management operations.