By Cherry / Last Updated May 19, 2022

Why need to move unallocated space to C drive in Windows 10?

Unallocated space is blank disk space and does not belong to any partition, with which users can create a new volume or extend another partition. In most cases, users may want to extend another partition, especially the C drive, with the unallocate space. Why? That's mainly because the C drive is the partition where the operating system installed, and many programs are installed by default. With the daily use, many temporary files or caches are generated, too. Then the C drive is eay to get full and shows red bar in Windows File Explorer. What's worse, users will receive low disk space warning now and then. In this case, allocating the unallocated space to the C drive and making it larger is of great necessity.

3 Ways to move unallocated space to drive C in Windows PC

Here we provide you with 3 different methods to extend c drive in windows 10 with unallocated space (also work for in Windows 11, 8, and 7 computer).

Method 1: Windows Disk Management

Microsoft has kept the Windows Disk Management tool in Windows 10/11 which users can use to add their unallocated space to the C drive. First, you need to open Disk Management through the Run window by pressing the Windows key + R at the same time, then enter ‘diskmgmt.msc’ and click ‘OK’. Once Disk Management has loaded, right-click on the C drive, and select the "Extend Volume" option to extend the C drive with the unallocated space.

Extend

 

However, some users find the "Extend Volume" greyed out and the process cannot go smoothly. For example, when you can get unallocated space by shrinking D drive with Disk Management, but when you try to allocate unallocated space into C drive, you'll encounter the mentioned problem. That's because the unallocated space is not adjacent to the C drive, or the unallocated space is not on the righthand side. The Disk Management can only extend a partition with an adjacent unallocated space on its right side. 

Extend Volume Greyed Out

 

Fortunately, there are two other ways for you to move unallocated space to C drive.

Method 2: The ‘Move Partition’ tool in AOMEI Partition Assistant

The good news is that if Disk Management doesn’t work for you since the unallocated space and the C drive are not adjacent, you can turn to AOMEI Partition Assistant Professional Edition. This perfect specialist partition manager provide the "Move Partition", which can help move unallocated space next to C drive and then combine them into one. You can download the demo version and have a try first of all.

Downlaod Pro Demo Win 11/10/8.1/8/7/XP
Secure Download

1. Install and launch AOMEI Partition Assistant. You will now be able to see that the unallocated space is not adjacent to your C drive (which prevented you from using Disk Management). Right-click on the D drive and select ‘Move Partition’ from the menu.

Move Partition

2. In the window, you should drag the D drive towards the righthand side as shown in the illustration below and click OK. This will allow you to move the unallocated space to the C drive.

Move D Partition to Right Side

3. You will now find that the unallocated space is adjacent to the C drive. Next you can right click the C drive and select ‘Resize Partition’ to add the unallocated space to your system partition.

Resize Partition

4. In the window, you should drag the C drive towards the righthand side to increase the drive size with the unallocated space. Next, click OK and you will return the main window.

Specify C Drive Location

5. Finally, click on Apply in the top left hand corner of the window to submit the pending operations.

Apply Move and Resize Partition

Note:✎...
If the unallocated space is on the left hand side of the C drive, you can also use the Resize Partition function to add the unallocated space to the C drive.

Method 3: Directly merge the unallocated space to C drive

If you think that method 2 is a bit complicated, then you may prefer method 3 as it uses a simpler process to move the unallocated space to the C drive.

1. Install and launch AOMEI Partition Assistant. Next, right click on the C drive and select ‘Merge Partitions’ from the menu.

Merge Partitions

2. In the popup window you should select the partitions you want to merge and click OK. This will allow you to merge the partitions directly with the C drive without having to worry about where the unallocated space is located.

Add Unallocated Space to C Drive

3. Back in the main window you will be able to preview the new C drive size. You will need to click on the Apply in order to complete the merger of the partitions.

Apply Merge Partitions

 

Summary

In this article, we share you with 3 methods to help move unallocated space to C drive in Windows 11, 10, 8, 7. You can choose one according to your specific situation. Apart from the above functions, the AOMEI Partition Assistant Professional Edition also comes with many other amazing feeatures such as moving applications from one drive to another (it can help free up drive space), migrating OS to SSD, converting MBR and GPT without losing data, test SSD or HDD speed, etc. If you are using Windows Server system, you can turn to AOMEI Partition Assistant Server .