C Drive Full, D Drive Empty - What Should You Do?

If your C drive is full D drive is empty, you can delete D drive and extend C drive. If your C drive is full but D is nearly empty, you can transfer the free space from D drive to C drive or move apps from C drive to D drive. This post offers the complete details.


By Dervish / Updated on September 26, 2023

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My drive C is low on space

My C: drive (29.2 GB) is low on space. There is not enough space in my C drive to download new programs. And I found my D drive is empty. Thus, I shrink D drive to get an unallocated space. But when I try to extend C drive with it, the option Extend Volume greyed out. How can I extend my C drive?”


C drive full for different reasons, such as unreasonable partition size allocation, installing too many programs, etc. C drive is where the operating system is installed, so generally, C drive needs to be allocated with enough space, and we should not install other third-party programs in it. Otherwise, your C drive will be getting full quickly, and your system will run slowly.

C Drive Full

What to do when C drive full and D drive empty?

So some people may use Disk Management to shrink D drive to get an unallocated space and extend C drive with it. However, the unallocated space you add to the C drive must be adjacent and behind the C drive. That is why the option Extend Volume greyed out. Then, what should you do?

Extend C Volume Grey Out

If the D drive is totally empty without a file saved, you can directly delete it to get contiguous unallocated space behind the C drive. Refer to the following part, and learn how to delete D drive and extend C drive.

Warning: D drive has to be adjacent to and behind C drive, otherwise Disk Management does not allow you to extend C drive with the deleted D drive.

1. Right-click computer> Manage > Storage > Disk Management. And the current partitions will be presented on the window. Right-click partition D and choose "Delete Volume".

Delete Volume

2. Click "Yes" to execute, and all data and files on the D drive will be deleted.


Warning: If the partition D has some files and it is currently used, you will be informed of this. You can click "Yes" to force the deletion of Partition D. But it might cause unexpected errors, please be cautious.

3. When the process finishes, you can see the space of D volume becomes an unallocated space. Right-click on C drive, and choose "Extend Volume".


4. “Extend Volume Wizard” will pop up, follow the prompts and click “Next

Extend Volume Wizard

5. In this window, select the disk(s) from which we want to get free space. And you can specify how much free space adds into the C drive. And click "Next".

Extend Volume Wizard Select Disks

6. Check the setting. And click "Finish". When the process is completed, your C drive will be extended, and D will be deleted.


C drive full, D drive empty - How to solve without data loss

If there is no data on D drive, you can delete it to get an adjacent unallocated space and extend C drive with it. What if your D drive has plenty of space while still has some necessary data? 

▶ Method 1. Allocate free space from D to C

In such a condition, you can turn to AOMEI Partition Assistant Professional, its "Allocate Free Space" function allows you to allocate unused or free space from D drive to C drive without deleting. You can download the demo version to see how it works:

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

Step 1. Install and open AOMEI Partition Assistant Professional. The condition of the disk will be displayed on the interface. Right-click the drive D or other partitions you want to allocate and choose "Allocate Free Space".

Allocate Free Space

Step 2. In the pop-up window, you could specify the free space to be allocated and choose which partition you want to extend.

Allocate From D To C

Step 3. Then click “Apply” to execute operation.

Apply Allocate Free Space

Note: After waiting, you have successfully extended the space of C drive. But in addition to this method, you can also use APP Mover to extend C drive. For details, please see method 2.

▶ Method 2. Move installed applications from C to D

If you don't want to change the size of C drive, you can use App Mover function in AOMEI Partition Assistant Professional to move apps from C drive to another drive without reinstalling. Please refer to the following steps:

Step 1. Install and launch AOMEI Partition Assistant, and then click "Free up" and "App Mover".

Step 2. There are two options, please click “App Mover” option. If you need to move folders from C drive to D drive, click “Move Folders” directly.

Two Options

Step 3. All your partitions will be listed in the window, the number and size of installed apps on every partition will also be displayed. Choose one partition that you want to move applications from and click "Next".

Step 4. All movable apps in the selected partition will be listed, choose applications you want to move and select the target location, then click "Move" (Take D as an example).

Step 5. You will see a pop-up message to confirm forcibly closing running applications when moving starts. Click "OK" to begin the process.

After completing the above operations, you will find that the selected application has been successfully moved to D drive, freeing the space of C drive.


That is how you can deal with the problem that C drive is full D drive is empty in Windows 11, 10, 8, 7. You can delete D drive and extend C drive with contiguous unallocated space within Disk Management. But when there are data that you don’t want to lose, AOMEI Partition Assistant is a nice choice.

In addition, AOMEI Partition Assistant also has other functions, such as migrate operating system to another drive, partition recovery, convert OS disk from MBR to GPT, and so on. And there is AOMEI Partition Assistant Server version, if your PC is running with Windows Server 2022, 2019, 2016, 2012, 2008, 2003, you can solve problem with it.

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.