How to Move Storage from the C Drive to the D Drive Securely?

How to move storage from the C drive to the D drive when Windows built-in Diskpart and Disk management won’t work. Here, another third-party powerful disk manager will be introduced so you can perform the storage transfer with much security and ease.


By Michael / Updated on May 12, 2023

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Why move storage from the C drive to the D drive?

Usually, a partition in terms of data, for example – the D drive - is much smaller than the C drive that’s the system drive. If you don’t pay attention, it can get quickly get full and clogged up with a large number of files. Thus, you’ll keep being prompted with the warning that you’re running out of space on the local disk D and what’s worse, the programs running on the D drive could become dramatically sluggish and you can’t install any more software to this drive either. Thus, when you encounter the fact that there’s not sufficient storage on the D drive, you can consider moving some storage from the C drive to it.

Why don’t Disk Management and Diskpart work anymore?

Windows has 2 sets of built-in programs for disk management with which people can extend partitions – Disk Management and Diskpart. Usually, if people want to get it done with either Disk Management or Diskpart, they have to shrink/delete a partition first, create a piece of unallocated space, and combine it with the target drive they want to extend. However, sometimes, they find the “Extend volume” option in Disk Management is greyed out or Diskpart shows errors. How come?

greyed out

The 2 programs are literally practical and powerful in many aspects but when it comes to partition extension, they work only on condition that the created unallocated space is right next to the target drive you want to extend. As we can see from Disk Management, the D drive is located on the right side of the C drive and thus, if you shrink or even delete the C drive, the unallocated space appears on the left of the D drive and so you can’t proceed with the drive extension.

How to move storage from the C drive to the D drive without data loss?

So, it’s a dead-end? Of course not! Since Windows built-in programs are not workable, why not turn to some third-party disk managers for help. This time, I recommend AOMEI Partition Assistant Professional that offers an exclusive feature – free space allocation – to move usable space between different drives in only a few clicks.

How to move disk space from C to D? Download the demo to move free space between drives with ease!

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Step 1. Install and launch AOMEI Partition Assistant Professional and wait until all hard disks and their partitions appear.

Step 2. Right-click on the C drive and select "Allocate Free Space" from the dropdown menu.


Step 3. Preset the amount of the storage space you want to allocate and meanwhile, choose a destination drive – here, it’s the D drive. Hit the button "OK".


Step 4. Click on "Apply" on the upper left of the home interface to commit the operation.


Note: For partition/drive extension, other features such as "resizing/moving partitions" and "merging partitions" are also available.

Optional way to free up the D drive space

To resolve the D drive full issue, besides allocating free space from the C drive, you can also free up the D drive itself by moving large apps from it to another drive that has enough storage space. You can achieve it still by using the AOMEI product as there’s another latest feature – app mover – that helps move programs including Microsoft Office, OneDrive, video games, and other third-party software from one partition to another without any data loss.



How to move storage from the C drive to the D drive losslessly? Here, the best alternative to Windows Disk Management and Diskpart – AOMEI Partition Assistant Professional - are provided for you to easily transfer storage from the C drive to the D drive. Meanwhile, you’ve learnt to free up the D drive by moving its apps to another place. If you want to try the AOMEI product on Servers, you can try the Server edition.

Michael · Staff Editor
Michael is a professinal editor of AOMEI editor team.