How to Extend C Drive in Windows Server 2008 R2 Safely

by John, Updated on: August 24, 2022

When C drive is getting full in Windows 2008 server, besides cleaning disk to reclaim space, you'd better extend C drive as large as possible. Nobody likes to waste a long time to recreate partitions and restore everything from backup. To extend C drive in Windows Server 2008 (R2), you may try Windows native Disk Management tool and third party software. Disk Management only works under specific condition. This article introduces detailed steps to extend C drive in Server 2008 (R2) no matter how your server is configured. Select corresponding method according to your own disk partition configuration.

How to enlarge C drive in Windows Server 2008 without any software

Windows Server 2008 has 2 native tools to help change partition size - Diskpart and Disk Management. Both tools have the ability to extend partition without losing data (in most cases). Diskpart works via command prompt, Disk Management has "Extend Volume Wizard" with graphical dialog-box. They work in different way but they have same restrictions while extending C drive in Windows Server 2008 (R2). There must be adjacent  "Unallocated" space on the right of the partition that you want to extend. Otherwise, Extend Volume is grayed out.

As you see in the screenshot, Extend Volume is disabled to C and E drive after shrinking D. Because Unallocated space can only be made on the right of D when shrinking this partition with either native tool. This Unallocated space is nonadjacent to C drive and is on the left of E drive. To extend C drive in Server 2008 (r2) without any software, you must delete partition D to get contiguous Unallocated space.

Extend greyed

How to extend C drive in Server 2008 R2 with Disk Management tool:

  1. Transfer all files in D: drive to other place. (Caution: if you installed programs or Windows services in this volume, do not delete it.)
  2. Press Windows + R keys on your keyboard, type diskmgmt.msc and press Enter to open Disk Management.
  3. Right click D: and select Delete Volume.
  4. Right click C: and select Extend Volume.
  5. Available disk space is selected by default, simply click Next.
  6. Click Finish to confirm extending.
  • If you like to use command prompt tool, follow the steps to extend C: drive in Server 2008 with diskpart command.
  • If there's no right adjacent partition or you cannot delete it, or if it is a Logical drive, neither Disk Management nor diskpart can help you. You must run third party software.

How to extend C: drive in Server 2008 R2 by shrinking D/E

With server partitioning software, you can make Unallocated space on either left or right while shrinking partition. After that, you can move and merge Unallocated space to either contiguous or any nonadjacent volume on the same disk. In this way, you can increase C drive space without deleting partition or losing any data. Operating System, programs and associated settings as well as anything else keep the same with before.

Better than other tools, NIUBI Partition Editor has innovative technologies to protect your system and data:

  • Virtual Mode - all operations will be listed as pending for preview before clicking "Apply" to take effect.
  • Cancel-at-will - if you applied wrong operations, you can cancel the ongoing operations without damage partition.
  • 1 Second Rollback - if it detects any error while resizing partition, it automatically reverts server to original status in a flash.
  • Hot Clone - clone disk partition without server interruption. You can clone system disk regularly and boot from clone disk immediately when system disk is down.

In addition, it is 30% - 300% faster because of the advanced file-moving algorithm. It is very useful especially when this server has large amount of files.

Download NIUBI Partition Editor, you'll see all disk partitions with structure and other information on the right, available operations are listed on the left and after right clicking. In Disk 0, there is drive C, D, E and a system reserved partition, original size of partition C is 40GB.

NIUBI Partition Editor

How to extend C: drive in Windows Server 2008 R2 with NIUBI Partition Editor:

Step 1: Right click D: drive and select "Resize/Move Volume", drag left border towards right in the pop-up window, or enter an amount in the box behind "Unallocated space before" (1024MB = 1GB).

Shrink D

Then drive D is shrunk and Unallocated space is made on the left.

Shrink D

Here D is the adjacent partition behind C drive, if it is E in your server, simply replace D with E in this step.

Step 2: Right click C: drive and select "Resize/Move Volume", drag right border towards right to combine this Unallocated space.

Extend C drive

Then the C drive is extended to 60GB.

Extend os drive

Step 3: Click Apply on top left to take effect.

If you want to enlarge C drive with a nonadjacent partition (such as E: in my server), you should move Unallocated space next to C drive before extending.

Video guide to extend C: drive partition in Windows Server 2008 R2 with other volumes:

Video guide

How to expand system C: drive with another disk

If there's only single C drive in Disk 0, or there's no available free space on the disk, no software can extend C drive with free space in other separate disk. In that case, you can clone this disk to a larger one with NIUBI Partition Editor, additional disk space can be added to C drive while cloning.

The separate disk means Disk 0, 1, etc that are shown by NIUBI or Windows Disk Management, no matter it is SSD, HDD, RAID or VMware/Hyper-V virtual disk.

How to extend C: drive partition by cloning to a larger disk:

Video guide

If there are several partitions and you don't want to copy disk to a larger one, you can move a partition to another disk, then delete it and add its space to C drive.

Extend C drive in VMware/Hyper-V running Server 2008

If there is available free space in any partition on the same disk, you can expand C drive by following the method above and there is no difference, no matter you use any types of SSD, HDD, RAID arrays or VMware/Hyper-V virtual disk.

If there is no available free space in entire disk, the method is different according to your storage device.

To extend virtual partition C for VMware or Hyper-V:

  1. Follow the steps to increase virtual disk in Hyper-V or VMware, then additional space will be shown as Unallocated space on the end of disk.
  2. Follow the steps above to move and add Unallocated space to C: drive (and other partition).

To extend C drive partition on RAID array:

Firstly, confirm if your RAID controller support RAID expansion with larger disks or adding more disks. If it does, then additional space will be also shown as Unallocated at the end after rebuilding RAID array.

If it doesn't, follow the steps above to copy original RAID virtual disk to other physical disk or new RAID array.

Find out your disk partition structure and configuration, then select the corresponding method to enlarge C drive for Windows 2008 Server. Besides shrinking, moving, extending and cloning disk partition, NIUBI Partition Editor helps you do many other operations.