Windows Server: Merge C Drive and D Drive by 3 Steps

▶ Q: Can I merge C drive with D drive in Server?

“I have a problem that my system partition with Windows Server 2012 installed is too small to install more software, while the D drive has a lot of free space that can be used to merge these two partitions together to increase the capacity of C drive?”

▶ A: You can merge C drive and D drive in Server via 2 methods

To merge C and D partition in Windows Server, you can try the following 2 methods. One is to make use of Server Disk Management while another one is applying a 3rd partition manager.

Method 1. Combine C drive with D drive via Disk Management

In Windows Server Disk Management, you cannot directly merge C drive and D drive since there is not such options like merge or combine partitions. The only solution is to delete partition D, making it an unallocated space, and then you can merge this unallocated space into C drive. At the same time, the D drive must be adjacent to the C drive on its right side.

Warning: To delete partition D means you will lose all your data in it, so please make a backup or move the data to another location.

Step 1. Press ”Windows + R” simultaneously, input “diskmgmt.msc” and click ”OK”.

Step 2. Right-click D drive, choose ”Delete Volume” and click ”Yes” to confirm.

Step 3. Right-click C drive and choose Extend Volume.

Step 4. Follow the prompts to complete the operation.

Note: In Server 2003 Disk Management, there is no “Extend Volume” option. So you cannot merge C and D in Server 2003 via this method.

Method 2. Directly merge C and D without losing data

To combine C drive with D drive without deleting partition, you can turn to a third-party partition manager software for Windows Server: AOMEI Partition Assistant Server. It is compatible with Windows Server 2025/2022/2019/2016/2012 (R2)/2008(R2)/2003 and Windows 10/8.1/8/7, XP and Vista. After merging, you can see an enlarged C drive and a folder named D drive, which contains all data saved in the previous D drive.

Now, install and run AOMEI Partition Assistant Server on your machine and refer to steps on how it merges two partitions: C drive and D drive in Windows Server. You can download its demo version to have a try!

Step 1. In the main interface, right-click C drive, choose “Advanced” and select "Merge Partitions".

Step 2. Tick the tick adjacent partitions (merge unallocated partition is not in this limit) you want to operate. Here choose partition C and D. Click "OK" to continue.

Step 3. Then a preview of this operation comes out. To make it into effect, click "Apply" at the top-left corner.

Notes:
①Only two partitions can be combined at one time and these two partitions must be contiguous. But you can merge two or more unallocated space into a partition no matter whether the unallocated space is contiguous to the partition.
②The host partition needs to have at least 1GB free space before merging.
③You can merge data partition into system boot partition, but you cannot merge system boot drive into data partition.
④If the C drive full while D drive has plenty of space, you can also use the partition manager software’s Allocate Free Space to allocate free space from D drive to C drive rather than merge these two partitions.

Summary

So, it is possible to merge C drive and D drive in Server 2025/2022/2019/2016/2012. Two methods are available for your selection. In addition to merging two adjacent partitions or merging unallocated space into existing partition, the AOMEI Partition Assistant Server can also finish other challenging disk partition operations, such as recover deleted partitions, clone partition, move partition, clone hard disk, convert MBR and GPT without removing partitions and so on.