By Lucas / Last Updated August 16, 2022

Why do you need to shrink C drive?

Shrinking volume from C drive takes full advantage of a disk that does not use its all space.

Especially nowadays, most PC has one internal disk that has only a C drive. If you want to separate your system and the data files for safety, you can shrink the C drive and create a new partition to store your data files and other programs. 

Anyway, no matter what factor leads you to shrink the system drive, the most important thing is to find out how to do this. The following parts will discuss three methods for shrinking C drive in Windows.

Shrink C drive with Windows built-in tools

Here in this part, it will take shrink C drive partition with built-in tools. However, before you start, clean up some of the crap first. You can empty the recycle bin and delete useless files on the C drive. Next, create a system image for your computer. These methods won’t cause data loss but you cannot be more careful in dealing with system and data.

Disk Management: Shrink C drive in GUI

Firstly, right-click "Computer"-> "Manage"-> double click "Disk Management" and right-click the C drive, select "Shrink Partition". It will query volume for available shrink space.

Shrink C drive

Secondly, type in the amount of space that you want to shrink by or click the up and down arrows behind the box (no more than 37152 MB).

Shrink size

Finally, you will see the unallocated space next to C drive.

Command Prompt: Shrink C drive via command lines

Diskpart is one of the built-in partition tools in Windows, which is an embedded product that needs to be used under Command Prompt. Press + key at the same time to start Run box. Type cmd and press Enter key to start Command Prompt. Then type the following commands and press "Enter" after each:

• Diskpart
• list volume
• select volume x (x is the volume number you want to shrink)
• shrink desired=10240 (size stands for the capacity you will shrink by and the unit is MB)
• exit

Why cannot shrink C drive?

When shrinking C partition with Disk Management, you are likely to encounter one confusing situation. For example, you have 909 GB on your C drive. However, when you plan to shrink this partition only to find the available space is only 297 MB according to the querying results. While at the top of the screen, it indicates that C drive has 472 GB of free space. What is wrong?

Well, the answer is the size of the available shrink space can be restricted by the amount of space currently allocated to on the hard drive for the virtual memory page file, system protection maximum storage space size, and hibernation files.

The location of the files on the hard drive plays a big part here because these files are marked as unmovable. Disk Management is unable to relocate them. If these files are located in the middle of the total amount of free space on the disk, then only the free space on the other side (usually its right side) can be used to create a new partition.

 What’s worse, even though there are no obstructive unmovable files, you can only shrink half space of the total amount with Disk Management.

Best free tool to shrink C Drive

It is time to turn to a third-party partition manager when Windows snap-in programs won’t work. You can try AOMEI Partition Assistant Standard which can relocate those files without damaging any of them. It is an all-around and comprehensive application that integrates simple-to-handle options for disk and partition management.

The Standard edition is a freeware that has earned a good reputation among worldwide users. It can also be used to shrink C drive in the VM machine. In fact, if you wish to shrink C drive to create a new drive, we suggest you upgrade to the Professional Edition to use the "Split Partition" feature to directly partition your C drive without formatting.

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Tip: To shrink C drive in Windows Server 2022/2019/2016/2012()R2/2008(R2)/2003, you can refer to AOMEI Partition Assistant Server edition.

Step1. Install and run this software. Right-click C drive and select "Resize Partition" or select this option in the left panel (you can see the free space of C drive is 29.87 GB).

Resize System Partition

Step2. Type in the amount of space or drag the double-headed arrow to resize.

Shrink System Partition

Step3. A gray unallocated space just behind C drive, click "Apply" to execute operations.

Apply Resize System Partition

Notes: If the C drive is in using, so the program will finish these operations in restart mode automatically.

After shrinking the C drive, there is unallocated space behind the C drive. You can use the "Merge partition" feature to extend your data partition. This function allows users to merge unallocated space that's not on the right side of the target drive.

To sum up

AOMEI Partition Assistant can help you do the task that the built-in tool can’t. Another way to make use of space in C drive is to create partition in C drive directly. Except for shrinking C drive more than half space, you can use it to move partition, merge partitions, copy disk, convert system disk from MBR to GPT disk for Windows 11, and more advanced function, command line partition.