How to Merge Unallocated Space to a Partition/Free Space

Want to merge unallocated space to the C drive or other partitions? You can use Disk Management and MiniTool Partition Wizard. These two methods are suitable for different application scenarios.

How to Merge Unallocated Space Using Disk Management

Step 1: Press Win + X and then select Disk Management to open it. Right-click the partition before the unallocated space and choose Extend Volume.

Step 2: Follow the wizard to add the unallocated space to the partition. You can keep the default options.

How to Merge Unallocated Space Using MiniTool Partition Wizard

MiniTool Partition Wizard is a free partition manager that can help you extend and move/resize a partition easily. Here is how to merge unallocated space to the C drive using this software:

MiniTool Partition Wizard FreeClick to Download100%Clean & Safe

Step 1: Launch MiniTool Partition Wizard. Select the partition (C: drive, for example) you want to expand in the right panel. Then, click Extend Partition from the left action pane.

Step 2: Expand the “Take Free Space From” menu and select an unallocated space. Then, drag the sliding handle to decide how much free space to take. After that, click OK.

Step 3: Preview the partition expansion effect in the right panel. Then, click Apply to save the changes.

How to Merge Two Unallocated Spaces into One

An unallocated space may be divided into 2 unallocated spaces by a special partition like the EFI, System Reserved, Recovery, etc. In this case, you can use MiniTool Partition Wizard to move the partition’s location to merge the two unallocated spaces into one. Here is the guide:

Step 1: In MiniTool Partition Wizard, click the special partition located between 2 unallocated spaces. Then, select Move/Resize Partition from the left action panel.

Step 2: In the pop-up window, move the entire partition to the left or right to merge the 2 unallocated spaces. Then, click OK.

Step 3: Preview the combination effect and click Apply.

Fix: Merge C Drive and D Drive in Windows 10/11 without Data Loss

To merge C drive with another Drive in Window 10 will enlarge the boot partition. MiniTool Partition Wizard helps extend C drive Window 10 with ease.

Read More

What If the Unallocated Space Can’t Be Merged

On a Windows PC, if the unallocated space can’t be merged, the reasons are usually as follows.

Reason 1: This is an MBR disk with a capacity exceeding 2TB. The space beyond 2TB will become unallocated space and cannot be added to other partitions.

To solve the issue, you can delete all partitions on the disk and then convert the disk to a GPT disk (right-click it in Disk Management and choose Convert to GPT Disk). Of course, you can also use MiniTool Partition Wizard to convert the MBR disk to GPT without data loss.

Reason 2: This is a GPT disk. There is a hidden MSR (Microsoft Reserved Partition) between the two unallocated spaces, or between the partition and the unallocated space.

If the partition and unallocated space are adjacent but cannot be merged, or if the unallocated space on a GPT disk is separated into two by an unknown entity, the most likely reason is that the MSR partition is blocking the way. The MSR will not show in Disk Management, but in DiskPart.

To solve the issue, you can delete the MSR partition using DiskPart. Here is the guide:

1. Press Win+ R, type “diskpart”, and press Enter to open it.
2. Type “list disk” and press Enter.
3. Type “select disk *” and press Enter. * is the number of the disk where the MSR partition is located.
4. Type “list partition” and press Enter.
5. Type “select partition #” and press Enter. # is the number of the Reserved partition.
6. Type “delete partition override” and press Enter.

Further Reading:

A Microsoft Reserved Partition (MSR) is a mandatory, small (typically 16-128 MB) hidden partition on Windows systems using GUID Partition Table (GPT) disks. It reserves space for potential system-level tasks, such as converting basic disks to dynamic disks, and contains no user data.

If you need to create it manually, you can use this DiskPart command: Create Partition MSR (Size=*) (Offset=*).

This article shows you 2 methods to merge unallocated space to a drive. It also tells you why the unallocated space fails to merge and is divided. Click to Tweet

Bottom Line

This post shows you how to merge unallocated space to a partition easily using Disk Management and MiniTool Partition Wizard. You can pick one according to your condition.

In addition, unallocated space may be blocked by a special partition, preventing you from merging it with other partitions. This post also offers the solutions.

If you have any questions or suggestions while using MiniTool Partition Wizard, you can contact us via [email protected] to get a quick reply.