By AOMEI / Last Updated July 25, 2017

Disk Management is built-in tool in Windows 8 which can help the users manage partitions to optimize the performance of their computers. It is an improvement of Microsoft Management Console which enables the users to manage hard disk without downloading or paying for any software.

Main features:

  • Extend and shrink volume
  • Create, delete and format volume
  • Convert basic disk to dynamic disk
  • Add or change drive letter
  • Convert MBR disk to GPT disk or GPT to MBR
  • Convert dynamic disk to basic disk
  • Mark partition as active

The limitations:

  • You cannot extend OS partition if there is no contiguous unallocated space on the right side of OS partition. In such case, the "Extend Volume" option will be grayed out in the disk management console.
  • You cannot extend OS partition by shrinking data partition behind it. Because "Shrink Volume" feature only generates unallocated space on the right side of the partition you shrink.
  • You cannot convert MBR disk to GPT disk or GPT to MBR before you delete all the existing partitions.
  • You can not shrink the partition to the size of minimum.

Windows 8 Disk Management built-in "Shrink Volume" feature supports to reduce partition size and generate unallocated space. Can you redistribute the unallocated space to any partition within Windows inbuilt disk management? Let us check it step by step.

Step1: Right-click "Computer", select "Manage" and then click "Disk Management" in "Storage" folder to open Windows 8 Disk Management. Right click on the volume which you want to shrink and select "Shrink Volume" as below:

shrink volume

Step2: In the pop-up window, enter the amount of space to shrink.

shrink d

Then you can preview an unallocated space behind D drive. When you right click on it, you can only see "New Simple Volume" that allows you to create a new partition.

unallocated space

There is another way to shrink hard drive partition in Windows 8: shrink volume in Windows 8 via CMD. It is an advanced partition manage tool. If you cannot shrink volume in Disk Management, you may try to do that using Diskpart in Command Prompt.

How to shrink volume Windows 8 in CMD?

1. Type “cmd” in search box and find CMD program. Right click it and select “Run as Administrator”.

2. In the Command Prompt, type following commands and press Enter after each input.

  • diskpart

  • list volume

  • select volume n (n is the volume you want to shrink)

  • shrink desired=10240 (you can replace 10240 with any other size you want)

  • exit


You may get an error indicates that you cannot complete the shrink in Windows 8. This is because there are some unmovable files like page file and hibernation file locate in the middle of the volume. In that case, you can turn to AOMEI Partition Assistant Standard, the free partition shrink software, to shrink volume beyond half.

The new generated unallocated space is always on the right side of the partition in Windows 8 disk management. However, the "Extend Volume" can only extend the partition that has an unallocated space behind it. So the unallocated space which is not next to C drive can't be added to system partition.

AOMEI Partition Assistant, as a magic partition software for windows, has many powerful and versatile features to manage disk partition safely and easily. As for the unallocated space, wherever its locations, AOMEI can move it to any partition. With the help of it, you can extend your C drive freely. Free Download AOMEI Partition Assistant Standard Edition (File Size: 7.65 MB)

Tips: AOMEI Partition Assistant is also fully compatible with the latest Windows 8.1, and the steps of shrinking volume in Windows 8.1 are the same as those to shrink volume in Windows 8. What’s more, it also can work on Windows 7, Vista, XP, 2000.

Before you do:

  • Make sure there is unallocated space on your disk, if there is no, you can resize partition to get unallocated space
  • If there are other applications running on the partition which you are going to perform, AOMEI Partition Assistant will notice you to close those applications or to execute this operation in PreOS Mode.

Step1: Install and launch AOMEI Partition Assistant Standard Edition. This is the main interface and you can see before the operation the size of C drive is 128.73GB.


Step2: Right click the partition (here's C) which you want to extend and select "Merge Partition".

merege partition

Step3: In the pop-up window, click C drive and the unallocated space. Click "OK".

click ok

Step4: Click "OK". You can see C drive has been extended to 248.03GB . Please click "Apply" to commit the operations.


From the above, we can make conclusion that Windows 8 Disk Management has some limitations , it allowing shirking partition to create new volume only, but can't add the unallocated space the partition that not next to it. However, with the help of AOMEI Partition Assistant, you can add unallocated space to C dive easily to get rid of the annoying warnings of low disk space error and improve the performance of your computer.

In addition, this partition software can help you migrate OS to SSD, make bootable CD, create/delete/format partition, resize/move partition. So AOMEI Partition Assistant maybe the wise choice to make the best use of disk space.