Merge Unallocated space

Merge non-adjacent Unallocated space to C drive

This article introduces how to merge non adjacent Unallocated space on Windows 10/8/7/Vista/XP and Server 2019/2016/2012/2008/2003, how to move and add nonadjacent Unallocated space to C drive.

Merge contiguous Unallocated space

If you want to merge Unallocated space to continuous partition, you can accomplish with Extend Volume functionality of Windows Disk Management utility. For example: when there is contiguous Unallocated space behind drive D, you can do like this:

  1. Press Windows and R key on keyboard, type diskmgmt.msc and press Enter to open Disk Management.
  2. Right click drive D and select Extend Volume.
  3. Click Next till Finish in the Extend Volume Wizard window.

It is easy, but you can only combine Unallocated space to the partition that is adjacent and on the left side with Disk Management.

To show you the restriction of DM, I shrank drive D and get 20GB Unallocated space behind it. As you see, Extend Volume greyed out for both drive C and D.

Extend Volume greyed out

To combine Unallocated space to the right drive E: or nonadjacent drive C, you need 3rd party disk partition software.

Download NIUBI Partition Editor, right click E and select “Resize/Move Volume”, drag the left border leftwards in the pop-up window. Unallocated space will be merged into drive E.

Extend E

Move nonadjacent Unallocated space

Disk Management cannot merge nonadjacent Unallocated space to C drive or other partition, to do this, first run partition editor to move non contiguous Unallocated space to either side of the drive that you want to extend.


How to move Unallocated space to be adjacent:

Right click drive D and select “Resize/Move Volume”, drag the middle position towards right side in the pop-up window.

Move D

Click OK, NIUBI moved Unallocated space to the left side of D.

Unallocated moved

Add/combine non adjacent Unallocated space to C

After the step above, the non-adjacent Unallocated space has been moved to behind C drive.

How to combine Unallocated space to C drive:

Right click C drive and select “Resize/Move Volume” again, in the pop-up window, drag the right border rightwards in the pop-up window.

Extend C

Click OK, Unallocated space is added into C drive.

System drive extended

Tip NIUBI Partition Editor is designed to work in virtual mode, to modify real disk partition, you need to click Apply to confirm.

In Summary

Windows native Disk Management can only do some basic operations such as create, delete and format partition. Because of some serious limitations of Shrink and Extend Volume feature, Disk Management is useless to repartition hard drive in most situations.

  • Shrink Volume cannot produce Unallocated space on the left side when shrinking a volume (such as D:), so Unallocated space is always non adjacent to drive C.
  • Extend Volume can only extend the partition with adjacent Unallocated space, furthermore, Unallocated must be on the right side. All other partitions cannot be extended.
  • Disk Management cannot move Unallocated space or any partition.

Luckily, you can solve these problem easily with NIUBI Partition Editor. Drag the border towards the other side in the pop-up window of Resize Volume feature, you can combine Unallocated space to either adjacent partition. Drag the middle position to other side, you can move Unallocated space.

To add/merge non adjacent Unallocated space to C drive or other partition, you just need 2 steps to move it contiguous and then combine.