How to Change Partition Size in Windows Server 2012 R2

by Jacob, Updated on: July 11, 2022

Hard drive partitions are allocated when you installing Operating System or by server manufacturer. Many people need to change partition size after running the server for a period of time. The typical example is that C drive is getting full, so they want to increase C drive space without reinstalling operating system. Or waste a long time to repartitions and restore from backup. Some other people want to shrink a large partition to create more volumes. Is it possible to adjust partition size in Windows 2012 server without losing data? The answer is yes. In this article, I'll introduce how to change partition size in Windows Server 2012 (R2) with native Disk Management and safe partition software.

1. Change partition size with Windows Server 2012 Disk Management

From Windows Server 2008, Microsoft added Shrink and Extend Volume functions in built-in Disk Management to help change volume size without losing data (not 100%). However, both functions have many shortages. Windows Server 2012 inherited the same functions without any improvement, so you'll encounter many issue when you adjust Server 2012 partition size with this native tool.

How to decrease partition size with Server 2012 Disk Management:

  1. Press Windows + X on keyboard and then select Disk Management in the list.
  2. Right click a NTFS partition and select Shrink Volume.
  3. Enter an amount of space and click Shrink. (If you don't enter an amount, maximum available free space is used by default.)

Shrink partition

How to increase partition size in Server 2012 R2 with Disk Management:

  1. Transfer all files in the right adjacent partition (such as D:).
  2. Right click it in Disk Management and select Delete Volume.
  3. Right click the left contiguous partition (such as C:) and select Extend Volume.
  4. Click Next till Finish in the pop-up Extend Volume Wizard window.

Extend volume disabled

Disadvantages to change partition size with Windows Server 2012 Disk Management:

  1. It can only shrink and extend NTFS partition, any other partitions are not supported.
  2. It can only shrink partition towards left and make Unallocated space on the right.
  3. It cannot shrink partition beyond the point where unmovable files are located.
  4. It can only extend partition when there's adjacent Unallocated space on the right.
  5. On MBR disk, Unallocated space that deleted from a Primary partition can't be extended to any Logical drive, Free space that deleted from a Logical drive can't be extended to any Primary partition.

In short, with Disk Management, you can only shrink a NTFS partition to create new volume, or extend a NTFS partition by deleting the right adjacent volume. If you want to extend a partition by shrinking another one, Disk Management cannot help you. As you see in the screenshot, after shrinking D: drive, Unallocated space is nonadjacent to C and on the left of E drive. Therefore, Extend Volume is disabled for both partitions.

Extend volume disabled

To change partition size in Windows Server 2012 (R2), third party safe partition software is better choice.

2. Adjust partition size in Windows Server 2012 with safe partition software

Comparing with Disk Management, NIUBI Partition Editor has many advantages such as:

There are many partition software that are able to change partition size for Windows server. But few software can ensure system/data intact while resizing partition. You'd better back up in advance and run the safest partitioning software.

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

  1. Virtual Mode - avoid incorrect operations by listing all as pending for preview, real disk partitions won't be modified until click "Apply" to confirm.
  2. Cancel-at-will - if you applied any incorrect operations, you can cancel the ongoing operations without damaging partitions.
  3. 1 Second Rollback - if it detects any error while resizing partitions, it automatically reverts server to original status in a flash.
  4. Hot Clone -  it is able to clone disk partition in Windows without rebooting server, so you can clone system disk as backup regularly. Whenever system disk is down, you can swap to the clone disk within several minutes.

Download this tool and you'll see all disk partitions with graphical structure on the right, available operations to selected disk or partition are listed on the left and by right clicking. In my test server, there are drive C, D, E and a system reserved partition in Disk 0. Original drive D: is 70GB and C: is 40GB.

NPE Server

How to change partition size in Windows Server 2012 R2 without losing data:

Shrink a NTFS or FAT32 partition to make Unallocated space. For example: right click D: drive and select "Resize/Move Volume". You have 2 options in the pop-up window.

If you drag left border towards right, or enter an amount in the box of Unallocated space before:

Shrink D rightwards

Then Unallocated space is made on the left side of D.

Unallocated produced

If you drag right border towards left, or enter an amount in the box of Unallocated space after:

Shrink D leftwards

Then Unallocated space is made on the right side of D.

Unallocated generated

Create new volume with this Unallocated space, or combine it to other partitions. To extend partition, right click C: or E: drive and run "Resize/Move Volume" again.

To extend C drive, drag right border towards right in the pop-up window.

Drag to extend

Then Unallocated space is extended into C: drive.

C drive extended

To extend E drive, drag left border towards left in the pop-up window.

Drag to extend

Then Unallocated space is extended into E: drive.

Drive E extended

Click Apply on top left to confirm and execute.

Watch the video how to adjust partition size in Windows Server 2012 (R2) without data loss:

Video guide

No partitioning software can extend a volume by taking free space from another separate disk, so if there is no available free space on a disk, you need to clone this disk to a larger one and extend partition with extra space. Watch the video

3. Change virtual partition size for RAID array, VMware, Hyper-V

If you want to resize RAID partition in Windows Server 2012 (r2), do not break array or do any operations to RAID controller, just follow the steps above. To Operating System and NIUBI, there's no difference if you use physical hard disk or any types of hardware RAID array.

If you want to change size of virtual partition for Windows 2012 server in VMware or Hyper-V, firstly, check if there's available free space on the same virtual disk. If yes, install NIUBI Partition Editor to the virtual server and follow the steps above. If there's no available free space on the same disk, you can expand the virtual disk without losing data, and then extend partition with additional disk space.

Besides help change partition size in Windows Server 2012/2016/2019/2022 and previous Server 2003/2008, NIUBI Partition Editor helps you do many other disk and partition management operations.

Download