How to merge Unallocated space in windows 10

Updated on: June 12, 2019

This article introduces how to combine Unallocated space in Windows 10 with built-in Disk Management and 3rd-party software. Partition software can merge non-adjacent Unallocated space to C drive by moving partition.

As its name, Unallocated space is part of disk space that is not allocated to any partition. Beside creating new partition, it can be combined to other partition and converted to part of unused space.

To get Unallocated space there are two options: delete and shrink a partition. After deleting a partition, all its disk space will be converted to Unallocated. Of course you'll lose all files in it. After shrinking a partition, only part of unused space will be converted to Unallocated, all files keep intact.

To delete or shrink partition, there are also two options: run Windows native Disk Management and third party software. There is no difference when deleting a partition, but Disk Management can only make Unallocated space on the right side when shrinking.

Merge Unallocated space in Windows 10 Disk Management

Disk Management uses Extend Volume function to combine Unallocated space, however, it can only merge Unallocated space to the left adjacent partition. To show you this limitation, I shrank D drive with the built-in Shrink Volume function.

Extend volume greyed

As you see, Extend Volume doesn't work for drive C and E. Because Unallocated space is non-adjacent to drive C and is on the left side of E.

If you want to combine Unallocated space to C drive with Windows 10 Disk Management, the only option is by deleting drive D, then:

  1. Right click C drive and select Extend Volume.
  2. Simply click Next till Finish in the pop-up Extend Volume Wizard window.

If you installed programs to drive D, do NOT delete it. Because all shortcuts and some programs will stop working even if you transfer all files to other partition.

If you want to merge Unallocated space to the right partition E, Disk Management cannot help you.

Combine Unallocated space with partition editor

To combine Unallocated space for Windows 10 computer, NIUBI Partition Editor is better choice. You just need to drag and drop on the disk map, Unallocated space can be combined to any contiguous and nonadjacent partition in the same disk.

Download NIUBI Partition Editor and you'll see the main window with all disk partitions, detailed parameters and available operations.

NIUBI

How to merge Unallocated space to adjacent partition

Combine to left adjacent partition (D:)

Right click volume D and select Resize/Move Volume. Drag right border towards right in the pop-up window.

Drag to merge

Then Unallocated space is merged into D drive.

Merged to D

Combine to right adjacent partition (E:)

Right click volume E and select Resize/Move Volume. Drag left border towards left in the pop-up window.

Drag to merge

Then Unallocated space is merged into E drive.

Merged to D

Merge nonadjacent Unallocated space to C drive

When C drive runs out of space, many people try to extend it under Disk Management, but encountered the problem that Extend Volume is disabled for C drive after shrinking D. As I explained above, this is because Unallocated space is non-adjacent to C drive. In this situation, you need to move Unallocated space to the left side with NIUBI Partition Editor, and then combine to C drive.

Steps to merge Unallocated space to C drive on Windows 10:

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

Move drive D

Then Unallocated space is moved to the left side of D.

Move Unallocated

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

Extend C drive

Then Unallocated space is combined into system C drive.

Extend volume C

Video guide to combine Unallocated space in Windows 10:

Video guide

Merge Unallocated space to other disk

If you want to combine Unallocated space in another separated hard disk (Disk 1) to C drive or other partitions in Disk 0, it is impossible. Because hard disk is a physical unit and the size is fixed. However, you can clone Disk 0 to another larger one with NIUBI Partition Editor.

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