Combine Partition and Unallocated Space in Windows 10

by Jane / Thu Aug 30 2018

How to combine two partitions or combine one partition with another unallocated space in Windows 10 for better managing disk partitions?

The method of combining partitions is another way of fixing low disk space problems in Windows 10, it’s also a common task to manage disk for the best use of the disk storage.

Many methods are suitable for this operation, we’ll list four of them

I: Combine Partition and Unallocated space

  • Disk Management: Extend Volume function
  • DiskPart.exe: extend command
  • Partition Expert: Resize/Move Volume function
  • Partition Extender: Auto Combine

II: Combine Two Partitions (Merge)

  • Disk Management: No such function
  • DiskPart.ext: No such command
  • Partition Expert: Merge Volume function
  • Partition Extender: Only Combine Free Space*

*Combine free space: Partition Extender can’t combine the entire partitions, but it can auto combine free space from one drive to another. For example, you want to combine C Drive and D Drive, in Partition Expert you can use the merge function to merge them into a large C Drive; in Partition Extender, you’ll get large C Drive + Small D Drive.

To begin with, we’ll assume the disk map on our computer looks like this and C Drive is an NTFS partition:

C: Drive
Unallocated space 1
D: Drive
Unallocated space 2

And our goals are to:

  1. Combine C Drive and Unallocated space
  2. Combine C Drive and D Drive

We’ll see how the above methods work on the same task:

Disk Management Extend Volume

I: Combine C + Unallocated Space 1

Open Disk Management by right-clicking on the Start button and choose the option, and:

  1. Right-click on C Drive
  2. Click Extend Volume
  3. Follow the guide

Then you’ll get:

C Drive + D Drive + Unallocated space 2

You can do the same on D Drive to combine D Drive and Unallocated space 2 to have only C Drive and D Drive on the disk

Goal 1: Completed

II: Combine C + D

Can’t combine C Drive and D Drive without deleting D Drive

Combine C Drive and D Drive mission failed in Disk Management

Goal 2: Failed

DiskPart.exe the command ‘extend’

I: Combine C + Unallocated Space 1

Press Win+R and type diskpart, then press Enter to use this command line tool, and:

  1. Type list volume and press
  2. Type select volume c and press
  3. Type extend and press

Then ‘Unallocated space 1’ is combined to C Drive, the same commands work on D Drive if you select volume D and extend

Goal 1: Completed

II: Combine C + D

Can’t merge C and D in diskpart.exe

No such command

Goal 2: Failed

Partition Expert Resize/Move Volume

I: Combine C + Unallocated Space 1

Partition Expert is a portable partition manager, so you can run it from the portable package if you don’t want to install it, and in Partition Expert:

  1. Click on C Drive
  2. Choose Resize/Move Volume from the sidebar
  3. Drag the handle to the end, click OK
  4. Click Commit

While combining, you can preview the effect in the mini disk map in the resize window

Goal 1: Completed

II: Combine C + D

As for goal 2, in Partition Expert, we can use the merge function to combine C Drive and D Drive with ease, steps can be:

  1. Right-click on C Drive (or D Drive)
  2. Click the Merge Volume function
  3. Check both C and D Drive in the list
  4. Specify “Merge Volume to:” C Drive from the drop-down list
  5. Click OK and Commit

Goal 2: Completed

After merged, there will be a folder named ‘D’ in the root directory of C Drive, it keeps everything which was originally on D Drive, so if you have some program relay on the path of D, make sure to change it to “C:\D”

Partition Extender auto combine

I: Combine C + Unallocated Space 1

The Partition Extender program is also portable, download the complete package or directly download the portable package (32-bit and 64-bit packages included), and run it, then use the steps below to combine C and unallocated 1:

  1. Click on C Drive
  2. Click NEXT
  3. Slowly Drag the handler to the right*
  4. Click OK and OK

Goal 1: Completed

II: Combine C + D

Combine C Drive and Drive in Partition Extender will no work, but if you want some free space from D Drive without deleting D Drive, Partition Extender would be the perfect solution

That said,

Goal 2: Failed

*Slowly Drag to preview the combining effect in the mini disk map, the steps like this: firstly it combine Unallocated Space 1 to C Drive, then if you keeping dragging, it will combine Unallocated Space 2 to C Drive, I know unallocated space 2 is behind D Drive, but unallocated space has a higher priority than free space in partition; And if you don’t stop, Extender will start to shrink D Drive after unallocated space 2 is completely combined


When comes to the mission combine partitions, Disk Management and DiskPart are not the best options, of course we can manually copy paste everything from one drive to another and then delete one partition and use the Extend Volume function or the ‘extend’ command to extend another partition, but when we have free portable programs like Partition Expert and Partition Extender, both combine partitions and combine partition with unallocated space operations are easy to complete

Learn more about Partition Expert and Partition Extender