At this time, we can consider dividing the space of the D drive to the C drive to increase the free space of the C drive. The following are the detailed steps on how to allocate the space of the D disk to the C disk in the win11 system: 1. Data backupBefore any disk operation, you must back up the data first. Back up important files and data from drive D to other disks or external storage devices to prevent data loss. It's like making a secure copy of your important files, just in case. 
2. Check Disk SpaceBefore you start the operation, you need to check the free space of drive C and drive. You can right-click on the C and D drives by "This computer" and select "Properties" to view the amount of free space in the pop-up window. It's like checking the amount of ingredients before you start cooking. 3. Compress files in the D driveIf there are a lot of unwanted files in the D drive, you can compress them first to reduce the space occupied by the D drive. You can right-click on the D drive by "This computer", select "Properties", and select "Compress this drive to save disk space" in the pop-up window. It's like putting a straitjacket on your files and reducing the space they take up. 
Fourth, expand the space of the C disk 1Open the Disk Management tool. You can search for "Disk Management" in the Start menu and open it. This tool is like a map of the disk that helps us find and manipulate the space of the disk.
2.In Disk Management Tools, locate the disk numbers of drives C and D. It's like finding the room number you want to move.
3.Right-click on the D drive and select "Compress Volume". Enter the compression amount in the pop-up window and click the "Compress" button. It's like telling the computer how much space you want to compress.
4.Right-click on the C drive and select "Extend Volume". In the pop-up window, click "Next", select the disk space you want to expand, and then click "Next". Wait for the system to complete the expansion operation. It's like telling your computer how much space you want to expand.
5.Close the Disk Management tool and complete the expansion operation. It's like closing your toolbox and getting your work done. 
5. After the expansion of the expanded space of the C drive is completed, you need to check whether the free space of the C drive has increased again. You can right-click on the C drive by "This computer" and select "Properties" to view the amount of free space in the pop-up window. It's like checking if your room has really gotten bigger. The above is the detailed steps to divide the space of the D drive to the C drive in the Win11 system. It should be noted that before doing any disk operation, be sure to back up your data first in case of data loss. At the same time, when expanding the space of the C drive, you need to select the appropriate expansion amount based on the actual situation to avoid affecting the system performance. It's like being careful not to destroy the structure of the house when decorating a room. 6. Clean up the space of the C driveIf you find that the space of the C drive has not increased much, it may be because there are some unwanted files or temporary files in the C drive. At this point, you can try to clear up the C drive space. Here are some common ways to clean up space on your C drive:1Disk Cleanup: Right-click on the C drive, select [Properties], and then click [Disk Cleanup] to delete all the cleaned files. It's like cleaning up clutter in your room. 2.Clean Storage: In Settings, find and tap Storage, then select Storage, tap Configure Storage, select Save Storage Now, and wait for the scan to complete before deleting all the apps you don't need. It's like clearing the storage space in your electronic devices. 3.Turn off System Restore: Right-click on the C drive, select [Properties], and then click [System Protection] to turn off the system restore function. This can reduce the footprint of the C drive. 4.Transfer files: Transfer important files from drive C to other disks or external storage devices to reduce the space occupied by drive C. It's like moving your ** from your computer to an external hard drive. 
7. Reallocate Disk SpaceIf none of the above methods can solve the problem, you can consider reallocating disk space. Here are the detailed steps to reallocate disk space in win11 system:1Open the Disk Management tool. You can search for "Disk Management" in the Start menu and open it. This tool is like a map of the disk that helps us find and manipulate the space of the disk.
2.In Disk Management Tools, locate the disk numbers of drives C and D. It's like finding the room number you want to move.
3.Right-click on the D drive and select Delete Volume. In the pop-up window, click the Yes button. It's like telling your computer that you're deleting a volume (i.e., a partition).
4.Right-click on the C drive and select "Extend Volume". In the pop-up window, click "Next", select the disk space you want to expand, and then click "Next". Wait for the system to complete the expansion operation. It's like telling your computer how much space you want to expand.
5.Close the Disk Management tool and complete the reallocation of disk space.
I hope it can help you, and I look forward to your likes and attention, thank you, thank you, thank you.