By AOMEI / Last Updated February 21, 2020

Why Need to Add Unallocated Space in Windows 10 Partition?

Unallocated space is space that doesn’t belong to any partition and no programs or data are allowed to write to it. Unallocated space can be used to store deleted files, but when Operating System saves another file in the same place, the previous data will be overwritten. In order to take full advantage of all your storage space, computer users will need to the add unallocated space to a partition in Windows 10, or create a new partition with the unallocated space.

We always recommend adding the unallocated space on your hard drives in Windows 10 to your partitions. Over time a number of files will build up on your system which will eventually use up a large amount of space. This could lead to a ‘low disk space’ warning on your system partition which will lead to your computer slowing down. Most users will experience this issue soon or later, so how do we fix it?

Of course, there is a method for you. That is adding unallocated space into partition windows 10, which means that you can extend partition with unallocated space. And then you can solve the low disk space in Windows 10.

How to Add Unallocated Space in Windows 10 Partition?

When using Windows 10 there are two common ways for you to add unallocated space to a partition. One is via the Windows 10 Disk Management tool, the other is via third party software.

Add unallocated space to a contiguous partition

Disk Management is a built-in tool in Windows 10 which is able to delete, extend, create, and format partitions. You can enter the tool by right-clicking This PC > Manage > Disk Management. When there is unallocated space next to the partition you want to add the unallocated space into, just right-click the partition and choose Extend Volume.

If the unallocated space shown in Disk Management is in the extended partition, then you will not be able to add it to your primary partition even if they are contiguous (please see this guide to move Free space out extended partition). As well as this, you will also be unable to add any unallocated space to a logical partition.

Extend Volume Greyed out

If you find yourself without unallocated space adjacent to the partition you want to add to, then the Extend Volume option will be grayed out. In the screenshot below you can see that the Extend Volume option has been grayed out in the popup menu as there is no unallocated space next to the C partition on Disk 0.

So, why does this happen? The Extend Volume function will only be enabled when there is unallocated space next to the primary partition or free space next to a logical partition.

Therefore, if you want to use Windows Disk Management you should make sure your partitions are compatible beforehand. If your partitions aren’t compatible and you want to add unallocated or free space to any partition, we would recommend using a specialist third party tool.

Merge unallocated space to any partition

AOMEI Partition Assistant Professional Edition is a powerful partition management tool, which can help you manage your partitions safely and efficiently. Using this software, you can add unallocated space into any partition (without losing any data) regardless of whether there is unallocated space behind the partition.

PS.: You can download the demo version of AOMEI Partition Assistant Professional to have a try!

Step 1: Install and run it. Right click the partition you want to add the unallocated space to and then choose Merge Partitions (e.g. C partition).

Merge Partition

Step 2: Select the unallocated space and then click OK.

Check Unallocated Space

Step 3: In the pop-up window, you will realize the size of partition has been increased. To perform the operation, please click Apply.

Apply Merge Partitions

Merging partition is not the only way to add unallocated space to a partition, you can instead extend the partition. Moreover, by allocating free space you can directly add free space from one partition to another partition.

This specialist software makes your PCs partition management much more convenient and simpler than ever before. If you are a computer user who wants to safely manage their partitions in Windows Server 219, 2016, 2012, 2008 and 2003, then AOMEI Partition Assistant Server is the software for you.