By Lucas / Last Updated March 21, 2022

The disk space which doesn’t belong to any partition is regarded as unallocated space by computer. This means no applications are able to write to the space. Unallocated space contains data from all files that have been deleted, but not yet overwritten. In order to make full use of unallocated space, you have to build a new partition with the space or add unallocated space to partitions for extending the size of partition.

Question 1: the hard drive of my computer has two partitions, partition C and partition D. In addition, there is still a piece of unallocated space right behind partition D. I want to install some other programs, but unluckily, there is not enough space in partition C now. Consequently, I decide to add the unallocated space to partition C. How can I realize it?

Question 2: I installed my operating system on C drive. Over time the data on this drive is getting larger. What’s worse, I am warned by low disk space, when I start my computer. However, I have large unallocated space at the end of this hard drive and there is a small piece of unallocated space about 7.8MB size between two data partitions. Is there any way to make full of them?

Answer: not only Windows 8 Disk Management, but also third party partition magic tool can aid you in committing the task "add unallocated space Windows 8" easily.

Notes: The PC is unable to directly save files to unallocated space unless it’s added to an existing partition or you create a partition from the unallocated space.

Disk Management is a Windows inbuilt utility to mange disks and partitions on your computer. With it, you can perform different operations including volume extension, volume shrinking, and disk format. Disk Management is easy-to-use and versatile. However, it has a limit – you can only add a piece of contiguous space to an existing partition for extension.

1. Right-click on “This PC”, select “Manage”, and then, select “Disk Management”.

2.Right-click on a partition that has contiguous unallocated space next to it and select “Extend Volume”

3. Follow the onscreen guide to merge them.

If the partition and the unallocated space is not contiguous, then, the option “Extend Volume” will be greyed out which means you can no longer merge them. In this case, AOMEI Partition Assistant Standard is free all-in-one partition magic software for disk partition which can meet your verified needs such as combining partitions, resizing partition, copying partition, making bootable CD, creating Windows To Go and resolve the problem at ease.

Tips: AOMEI Partition Assistant is also fully compatible with the latest Windows 8.1.

Now, free download the AOMEI Partition Assistant Standard Edition, and solve the problem at once.

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Step 1: Launch the software and you'll see the main interface.

Step 2: You can add unallocated space to partition C by right clicking the C drive, choosing "Merge Partitions" in the pop-up window to accomplish the task.


Step 3: Choose the unallocated space then click ok.


Step 4: Click "Apply" button on the toolbar.



AOMEI Partition Assistant should be the best free partition manager that helps you add unallocated space in Windows 8 easily and safely. It also allows you to move partition, create partition, and use many advanced features. If you upgrade to AOMEI Partition Assistant Professional Edition, you can get more advanced features, such as the function "Allocate Free Space" in dealing with resizing partition of there is no unallocated space. And there is Server Edition for Windows Server users.