How to Increase C Drive Space from D Drive in Windows 7, 8, 10, 11

How to increase C drive space from D drive to solve low disk problem in Windows 11, 10, 8, 7? Here are two ways you can try to extend C drive by taking space from D drive.


By Dervish / Updated on December 4, 2023

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Help!  “Can I increase C drive by taking space from D drive?”

“I have a desktop that comes with a small C drive and a large (and mostly empty) D drive. No matter how I try to get apps or programs loaded into D drive, everything goes to C drive and makes it almost full. Now I always receive the low disk space warning on C drive. Is there any way that I can increase C drive space from D drive, other than a fresh OS installation.”

Need to extend C drive space from D drive?

It is a common problem that as time goes by, the Windows C drive runs out of space gradually! While, the other partitions, like D drive, still have much free space. Even though some users have allocated disk space to each partition at the beginning, and allocated more space to C partition. However, it is still easier to get full than the other partitions because many programs are installed on system partition, a large amount of data are stored on system drive, OS running generated a lot of extra files, etc.

Anyway, how to solve such an issue? Uninstall some non-frequently used programs and reinstall them on other partitions, or move apps from C drive to another drive,  or delete unnecessary files? Supposed that C drive hasn't been allocated with enough space, you may wonder if it is possible to extend C drive by taking free space from D drive or other partitions with enough free space.

How to increase C drive space from D drive in Windows 11/10/8/7

Generally, to extend C drive by moving free space from C drive, you can make use of the Windows native there are two ways, using Disk Management (DM) or a third-party partition manager– AOMEI Partition Assistant. Below are details about those two ways.

▶ 1. Increase C drive from D drive via Disk Management

Before proceeding, you should note that Disk Management can only extend C drive when there is an unallocated space very behind it. Meawhile, when you shrink a parition, you can only get the unallocated space on its the right adjacent side. That’s why you will find the Extend Volume grayed out when you shrink D drive and try to extend C drive with the unallocated space.

Therefore, to increase C drive space from D drive, you have to delete the whole D partition and make it a contiguous unallocated space for C drive.

Note: Backup important data on D partition or just transfer them to other drives.

Step 1. In Disk Management, right click on partition D and select "Delete Volume" to create unallocated space for increasing partition C.

Delete Volume

Step 2. Right click system partition and choose "Extend Volume” to extend system partition. Still, follow the steps to complete the progress.


What if there is too much data on D drive and you do not want to delete it? Is there another way to increase C drive space from D drive? The next method can satisfy all your needs.

▶ 2. Allocate Free Space from D to C Drive with partition magic

AOMEI Partition Assistant Professional is a third party partition manager which can do not only what DM can do (such as extend partition, shrink partition, delete partition, create partition and format partition), but also what DM cannot do (like move partition, wipe disk, rebuild MBR, split partition, merge partitions, etc.). To increase C drive space from D drive, you can apply its “Allocate Free Space” features, which allows you to directly allocate free space from one drive to another without causing data loss. Only 3 steps can make it done:

Tip: You can download the Demo Version for a free trial.

Download Free Demo Win 11/10/8.1/8/7/XP
Secure Download

Step 1. Right click partition D and select Allocate Free Space.

Allocate Free Space

Step 2. Set how much space you want to allocate form partition D and choose C partition as a target partition.

Allocate From D To C

Step 3. Preview the result after allocation. If that’s what you want, just click "Apply" on upper left to carry out the operation.

Apply Allocate Free Space

1. If it looks not like what you want, or you want C drive to be larger, you can click Discard behind Apply and do the operations above once more.
2. You can also complete the “increase c drive space from d drive” task using Extend Partition feature of this software.


This is all on how to increase C drive space from D drive in Windows 11, 10, 8, 7. With two methods provided, you can make a proper choice based on your situation. Apart from extending C drive more flexibly and securely, AOMEI Partition Assistant Professional is also able to transfer C drive to SSD, align SSD partitions, clone system disk to SSD/HDD and more. If you are running Windows Server operating system, you can try AOMEI Partition Assistant Server.

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.