Add Unallocated space to C: drive in Windows Server 2012

Updated on: October 30, 2019

This article introduces how to add Unallocated space to C: drive in Windows Server 2012 R2. Move and add Unallocated space to system partition without data loss.

Can't add Unallocated space to C drive in Server 2012 DM

Windows Server 2012 has built-in Shrink Volume and Extend Volume functions in Disk Management to resize hard drive partitions. When system partition C: runs out of space, many people try to increase partition size, thinking shrink drive D: to get Unallocated space and add to C: drive.

In fact, Server 2012 Disk Management cannot add Unallocated space to system C: drive in this way, because both Shrink and Extend Volume functions have restrictions:

  • Shrink Volume can only make Unallocated space on the right side when shrinking any partition.
  • Extend Volume can only add Unallocated space to the left contiguous partition.
  • If drive D: is FAT32, it can't be shrank, because only NTFS partition is supported.

The only way to extend C: drive in Disk Management is by deleting D to get adjacent Unallocated space, then Extend Volume will be enabled.

However, in many servers, programs or some Windows services are running from drive D, so you can't delete it.

In addition, if drive D is Logical, you still cannot enlarge C drive after deleting it.

Extend volume disabled

In this situation, if there is tool that can move Unallocated space to the other side, this problem will be solved.

How to add Unallocated space to C drive

Download NIUBI Partition Editor and you'll see the main window with disk partition structure and other information. Unlike Disk Management, NIUBI lists the available operations to highlighted disk partition on the left (or by right clicking).

There is 20GB Unallocated space that is shrank from D drive via Disk Management.

NIUBI Partition Editor

Steps to add Unallocated space to C: drive in Windows Server 2012:

Step 1: Right click drive D: and select "Resize/Move Volume", drag middle position towards right in the pop-up window:

Move rightwards

Then Unallocated space is moved to the left side.

Move Unallocated space

Step 2: Right click drive C: and select "Resize/Move Volume" again, drag right border towards right in the pop-up window.

Expand C drive

Then Unallocated space is added into C: drive.

Unallocated add to C

Step 3: Click Apply on top left to take effect. (The operations before clicking Apply just work in virtual mode.)

If you shrank drive E: to get Unallocated space, it is similar just one more step to move Unallocated space.

Watch the video how to move and add Unallocated space to C drive in Windows 2012 server:

Video guide

Add Unallocated space to system partition from other disk

In few servers, there is no other partition in the same disk, or you can't get Unallocated space from all other partitions. Some people wonder whether it is possible to add Unallocated space to system C: drive from other disk. The answer is No. Because a hard disk is physical unit, a 500GB disk can't be decreased to 480GB or increased to 520GB.

In this situation, you can clone disk to a larger one with NIUBI. Extra disk space will be shown as Unallocated on the end of disk, then you can add Unallocated space to system partition (and other data volumes).

How to add more space to C: drive in Windows Server 2012 by cloning:

Video guide

In Summary

Windows Server 2012 Disk Management cannot make Unallocated space on the left side while shrinking, cannot move Unallocated space to the other side, so it cannot add Unallocated space to system partition C. With NIUBI Partition Editor, you can accomplish this task easily.

Comparing with other software, NIUBI is safer and faster because of its innovative technologies such as:

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