How to Merge C Drive and D Drive?

As a system partition, C drive should be easy to run out of space. Thus, the D drive which is adjacent to it will help a lot. Merge C drive and D drive could extend the space of C partition.


By Cherry / Updated on May 12, 2023

Share this: instagram reddit

It is known to us that C drive is very important to the computer. If the C partition is running out of space, it will make a big effect on the property of the whole system, even the speed of the operation. So, keep C drive a full space is truly necessary, and its neighbor D drive will give a big help to extend its volume.

Why Should We Merge C Drive and D Drive?

When the C partition hasn’t enough space, we must figure out a way to extend it. There are many ways to extend it. For example, wipe the trash files on the partition to reduce the using space or extend the whole volume by taking place from other partitions, such as merge C drive and D drive. Most people know that change the size of C: will restart the computer. But if we use the partition assistant to do it, we may avoid this damn thing.

Merge C Dive and D Drive without Restarting Computer

It’s very exciting for clients that extend the C partition without restarting computer. We can solve the problem easily by taking use of the AOMEI Partition Assistant Professional, an excellent tool which can resize partition, create partition, delete partition, and so on. What the important, it also supports the free download. The magic is that under the help of partition assistant, we will merge the two adjacent partitions into one without changing the data. It’s very convenient for us.

Before we using the partition assistant, there are some tips that we should follow:

1. Backup the important data by using backup software. Although the partition assistant will finish the task without losing data, we should keep an eye in case of the unexpected shut down or the power off.

2. Merge partitions require the two partitions adjacent with each other, or you can move partition so that they are neighbors.

3. If there are some programs running on the partition, the partition assistant will popup a dialog box to prompt you that it will operate under the PreOS Mode.

Step1.Install and launch AOMEI Partition Assistant. Right-click the C drive and select  "Advanced" > “Merge Partition” as the screenshot.

Merge Partition

Step2. After this step, it will display the following picture, and you can select the partitions you want to merge. Then, click “OK” to move on.

Tick D Partition

Step3.Here, you can see that there is only C drive but no D drive. But, it doesn’t mean that you have finished the job. Click the “Apply” at the left top.

Result Preview

Clicked the “Apply” will show you an interface which you should click the “proceed”, and after that, you have finished it yet. But if there is blue words said "Reboot required" like the following picture, it means the operation will proceed under PreOS.


In addition, using Partition Assistant to merge C partition and D partition is very simple and easy. Originally, it can run without restarting the computer and keep your data safe.

Cherry · Staff Editor
Cherry is an editor of AOMEI Technology, she covers backup & restore, hard disk & partitions management, cloud files transfer, website & database backup and so on for AOMEI. She enjoys helping people find solutions to their problems. She loves traveling, cooking, reading and so on. She takes most of time with her family when she is not working.