How to Add Unallocated Space to D Drive Without Data Loss

How to add unallocated space to D drive when there is not enough space? Here, 2 ways will be provided to extend D drive easily, including Disk Management and AOMEI Partition Assistant. In addition, it will offer a step-by-step guide.


By Dervish / Updated on August 25, 2023

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Why add unallocated space to D drive?

For many computer users, the unallocated space is a very important part. Although you cannot directly write files or folders on it, you still can make full use of it to enlarge another existing partition. Typically, add unallocated space to D drive for these reasons:

✦ Increasing Storage Capacity

If your D drive is running out of space, adding unallocated space to it can increase its storage capacity. This is particularly useful if you're dealing with large files, applications, or media.

✦ Simplified File Management

Having a larger D drive means you have more room to organize and store files, which can make file management simpler and more organized.

✦ Avoiding Fragmentation

When a drive is almost full, it can become fragmented as the system tries to fit new files into available spaces. Adding unallocated space helps prevent fragmentation by providing more contiguous space for new files.

✦ Future Expansion

Having additional unallocated space allows for future expansion. You might not need it now, but as your storage needs grow, you'll have the flexibility to allocate more space without the need for major reconfigurations.

In sum, add unallocated space to drive is a great choice to solve low disk space error, and it becomes more and more necessary for users.

How to add unallocated space to D drive on Windows 7/8/10/11

In this part, we will share you with 2 different options to merge unallocated space to D drive for Windows. One is Windows built-in tool Disk Management, and the other one is AOMEI Partition Assistant, which is free partition manager that can resize/merge partition more easily.

▶ Option 1. Extend D drive by using Disk Management

To add unallocated to D drive with Disk Management, you must pay attention to the following limitations:

① There must be one or more unallocated space.

② The unallocated space must be adjacent to the target partition.

③ The unallocated space must be at the right of the target partition.

Briefly, you can only add unallocated space to the adjacent partition which lies on its left hand. If your disk partition location meets this condition, do as the steps below.

Step 1. Right-click "This PC" and select "Manage". Then, click "Disk Management" udner "Storage" to open Disk Management.

Step 2. Click D drive, select "Extend Volume" to add unallocated space to D drive.

Extend D Drive

Step 3. The "Extend Volume Wizard" pops up and click "Next" here.

Extend Volume Wizard

Step 4. Click "Next" and follow all defaulted settings.

Extend Volume Wizard Select Disks

Step 5. Click "Finish" to finish the process. Now the unallocated space has been added to D drive.

Extend Volume Wizard Confirm

However, if it does not meet all above requirements (the unallocated space is not adjacent to D drive), you will find the extend volume is disabled. In this case, a professional partition manager like AOMEI Partition Assistant will be needed. Please turn to option 2.

▶ Option 2. Alternative to add unallocated space to D drive easily

AOMEI Partition Assistant Standard is a professional disk partition management tool which is designed to solve partition and disk problems in Windows 11/10/8/7/XP. With it, you can add unallocated space to any partition effortlessly. It offers you various choices, including Resize Partition and Move Partition, Merge Partition.

Besides, AOMEI Partition Assistant Standard has much more features, including wiping partition for reuse, removing junk files for more space, Rebuild MBR, etc. Now let’s see how to extend D drive with unallocated space.

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Solution 1. Resize Partition and Move Partition

Step 1. Install and run AOMEI Partition Assistant Standard on your Windows PC.

Step 2. Enter the main page, right click D partition and select Resize/Move Partition.

Resize Partition

Step 3. Drag the D Partition to the left and click OK. Also, you can drag it to the right if there is an unallocated space.

Drag To Extend D Drive

Step 4. Click Apply to start the pending operation.

Apply Add Unallocated Space To D

However, it still not perfect. It requires an adjacent unallocated space (on the right or left side). Besides, here is an easier way. You can merge D drive with any unallocated space as long as it's on the same disk.

Solution 2. Merge Partition

Step 1. Enter the main page, right click D partition, choose Advanced and select Merge Partition.

Merge Partitions

Step 2. Here, select the unallocated space and click OK.

Add Unallocated Space to D Drive

Step 3. Preview the result and click Apply.

Apply Add Unallocated Space to D

Step 4. Click Proceed to start the pending operation.

Proceed Merge Partitions

You can also refer to the steps to add unallocated space to C drive.

After switching to AOMEI Partition Assistant Professional, there are other advanced functions to extend d drive or other drives on Windows 11/10/8/7.
1. Extend Partition Wizard: Extend your system boot partition without rebooting Windows PC and other partitions.
2. Allocate Free Space: Allocate free space from one drive to another, saving the steps to create unallocated space first.


How to add unallocated space to D drive on Windows 7/8/10/11 is not a problem. As long as there is a right adjacent unallocated space to the target partition, you can use Disk Management. If not, you can use free partition manager AOMEI Partition Assistant.

AOMEI Partition Assistant can get rid of the limitation of Disk Management. You just need an unallocated space on the same disk. If the unallocated space on the right side, you can use Extend Partition Wizard. If not, you choose Resize Partition and Move Partition, Merge Partition as you like. If you want to add unallocated space to D drive in Windows Server 2022/2019/2016/2012/2008/2003, you can switch to AOMEI Partition Assistant Server.

Dervish · Staff Editor
Dervish is an English editor of AOMEI Technology; He is delicated to offering users easy and effecitve solutions for issuses related to disks and partitoins. In his spare time, he enjoy wathcning films, playing footable, traveling and so on.