How to Merge C Drive with Unallocated Space Directly in Windows 10 or 11?

Why do you need to merge C drive with unallocated space?

Your hard drive may not be divided well at the first time. You can even see that there is still an unallocated space on the hard drive when you open the Windows Disk Management. Meanwhile, the C drive is running out of space. Under these circumstances, merge C drive with unallocated space should be the best way to extend system partition. If there is no unallocated space for extending, you can get rid of unnecessary files, move installed apps from C drive to another drive, etc. 

Using Windows Disk Management to merge c drive with unallocated space

Windows Disk Management has been improved since Windows 7. You can use it to extend volume or shrink volume according to your requirements. If the unallocated space is at the right side of C drive and adjacent to C drive, you can use it to add unallocated space to C drive.

Right-click My computer, select Manage, and open the Disk Management. Then, right click the C drive, click Extend Volume.

Then, you can get into the extend volume wizard and merge C drive with unallocated space.

However, the Windows Disk Management supports you merge C drive with unallocated space only when the unallocated space adjacent to C drive and it must be at the right side of C drive. Otherwise, you cannot extend volume to unallocated space because the Extend Volume would be grayed out.

Windows Disk Management Alternative

As Windows Disk Management cannot merge C drive with unallocated space which isn’t adjacent to C drive, or at the left side of C drive. Here we recommend you the best Windows Disk Management alternative AOMEI Partition Assistant, which can help you add unallocated space to C drive no matter where the unallocated space is in Windows 11/10/8.1/8/7/XP/Vista. To merge C drive with unallocated space, here you can follow the steps below:

Step1. Install and launch AOMEI Partition Assistant, you will see the main environment of your hard drive. Right click the C drive at the main interface, then, select Merge Partitions at the pop out menu.

Step2. The, it will move to the window where you can add the unallocated space to C drive by selecting the partitions in the box. Click OK.

Step3.Here you can see that you have already extend system partition by adding the unallocated space to C drive. Don’t forget to click Apply to submit the whole operations.

Extend C drive with unallocated space should be the best way to enlarge system drive. You do not need to change a hard drive, or reingstalling windows, but add the unallocated space to C drive. Besides, AOMEI Partition Assistant can adjust your hard drive to the best status with Allocate Free Space if there is no unallocated space on your hard drive.