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

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. Here is a typical case from the Microsoft community:

"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?”

What to do when C drive full, D drive empty? Don't worry. This guide will provide 3 efficient solutions to fix the problem and let you know how to use D drive fully.

How to Fix C drive full, D drive empty - 3 Efficient Ways 

What if your D drive has plenty of space while still having some necessary data? By moving the important contents of the C drive to the D drive you can free up space on the C drive and fully use the D drive.

▶ Method 1. Allocate free space from D to C

AOMEI Partition Assistant Professional is a comprehensive disk and partition management tool. It offers several options to alleviate low disk space error, including extending partitions, deleting partitions, and more. Among them, its "Allocate Free Space" function allows you to allocate unused or free space from D drive to C drive without deleting.

With a simple interface, everyone can enjoy the better performance of their computers. You can download the demo version to see how it works:

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".

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

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

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. You can make better use of D drive by migrating applications.

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.

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. In addition, you can change the default location of software installation in the settings and save space on the C drive. If you are running out of space on your D drive, you can use AOMEI Partition Assistant to continue expanding space or optimizing performance.

Method 3. Extend C drive with the Deleted D drive

If there is no data on D drive, you can delete it to get an adjacent unallocated space and extend C drive with it. 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. 

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. The current partitions will be presented on the window. Right-click partition D and choose "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”

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".

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

In addition, you can also expand the C drive directly with AOMEI Partition Assistant. This tool breaks the Windows and disk management limitations and enables users to extend C drive with or without unallocated space successfully. Moreover, it can resize, move, and merge partitions to ensure optimal disk space utilization without losing data.

C Drive VS D Drive, Why C Drive Full, D Drive Empty?

Having solved your problem using the above methods, we can now explore why the "C drive is full, D drive is empty" problem occurs and prevent it from recurring. First of all, we need to know the difference between C drive and D drive:

• C drive provides storage media for device drivers and application software, it is also the default location for operating system and system files.
• D drive has more flexibility, it is mainly used to store different data and solve the problem of lack of space.

So if you download a lot of programs and games, the data may be saved to the C drive by default. In addition, many temporary files will take up the available space on the C drive. And D drive needs to be adjusted manually. Therefore, it is necessary to regularly monitor the storage capacity of C Disk and increase the space of C Disk.

Conclusion

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 is 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, converting 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 2025/2022/2019/2016/2012, and 2003, you can solve problems with it.