Allocate Free Space to C Drive without Deleting Partition in Windows 11, 10, 8, 7

What should I do when there is not enough space on the C drive? Don't worry about that, this page will show you how to allocate free space from one drive to C easily and safely.


By Dervish / Updated on March 7, 2024

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Why allocate free space in Windows 11, 10, 8, 7?

When the hard drive is not well-partitioned at the beginning, many users may meet “low disk space warning” on C drive or other data drives. To solve it, some users will clone a hard drive to a larger drive for more free space. Other users would like to allocate free space from one drive to another to distribute free space reasonably.

Here is a real user case:



When build computer two years ago, I had partitioned my hard disk. I thought I left enough memory for the system drive. However, with the increasing creating files and installing programs, the computer gave me a low disk space warning on C drive. I don’t want to replace the hard drive with a new one currently and the D drive has redundant free space. What should I do to add the free space to C drive from D drive?”


This problem is not uncommon in daily computing. In order to optimize the computer to get a faster running speed and work more effectively, many people try to find the best way to allocate free space to an existing partition. If you are interested, please continue reading.

How to allocate free space to C drive with Disk Management

Luckily, Windows Disk Management offers a way to allocate free space, which might be a little bit circuitous.

1. Press "Windows + R" to open Run, and then type "diskmgmt.msc" to open Disk Management.

Open DM

2. If there is unallocated space on the right side of the target partition, just right-click that partition and select “Extend Volume”. Then, the target partition will be extended via Extend Volume Wizard.


3. If there is no unallocated space on the right side of the target drive, you need to delete its contiguous partition to get adjacent unallocated space. Or, Extend Volume will gray out

Extend Volume Grey Out

Tip: Before deleting an adjacent partition, please backup this partition, otherwise the deleted data cannot be retrieved.

As talked before, Disk Management provides a roundabout solution for allocating free space to C drive in Windows 11, 10, 8, and 7. However, there is a better way to allocate free space to a target partition without deleting an adjacent partition or volume.

How to allocate free space to C drive easily and safely

When there is not enough space on the disk, how to extend it easily and safely? AOMEI Partition Assistant Professional is a powerful partition manager to help you allocate free space from one drive to another directly. The “Allocate Free Space” feature provides an easy-to-use wizard and the entire process will be completed with a few clicks. And it is compatible with Windows 7, 8, 10, and 11.

Free Download Win 11/10/8.1/8/7/XP
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Step 1. Install and open AOMEI Partition Assistant professional. Right-click the D drive and choose "Allocate Free Space".

Allocate Free Space

Step 2. In the new window, you can specify the space size and target partition. If it’s C drive, you need to select C drive from the given list, and click “OK”.

Allocate From D To C

Step 3. Now, you can preview that the C drive has been extended. Then, click Apply to save the changes.

Apply Allocate Free Space

Just in a few minutes, you can allocate free space on Windows 11, 10, 8, and 7 without data loss. Apart from the “Allocate Free Space” feature, AOMEI Partition Assistant Professional also provides other functions, such as moving programs to another drive, deleting large files, merging partitions, wiping hard drives for reuse, SSD secure erase, etc.

AOMEI Partition Assistant Server can help you allocate free space on Windows Server OS, like Server 2008, Server 2012, Server 2016, Server 2022, etc. Do you want to completely solve the unreasonable partition layout on your hard drive? Would you like a better operational computer? Now, download it to optimize your computer!

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.