By AOMEI / Last Updated July 24, 2019

What is unallocated space used for?

Unallocated space, sometimes called free space, is the logical space on a hard drive that operating system can write to.


In order to take full use of storage space, you can create a new partition or extend partition with unallocated space. For example, you may need to merge unallocated space to system partition in Windows 10 when a low disk space warning appears.

Make unallocated space

Not every disk has unallocated space according to the installation, but there are two ways to create unallocated space in Disk Management:

  • Delete volume. This method is not recommended because it will wipe data on the partition. In this case, you should do backup in advance, which takes more time.

  • Shrink volume. There won’t be data loss with this approach while some limitations exist. “Shrink Volume” only makes the unallocated space locate behind the volume you shrink. In other words, you can’t extend or merge unallocated space to system partition in Windows 10 directly if you shrink other volumes.

By this token, you’re suggested to employ a third-party partition software that helps you merge and manage partitions easily.

Merge unallocated space to system partition via AOMEI

AOMEI Partition Assistant is an easy-to-use disk/partition software with which you’re able to merge unallocated space to C drive in Windows 10/8/7 by a few of clicks without losing data. No matter how much unallocated space exist, you can add all to system partition once as long as they are on the same disk.

Step 1: Install and launch AOMEI Partition Assistant. If there’s no unallocated space, make some via “Resize Partition”.

Step 2: Right click C drive. Select “Merge Partitions”.

Merge Partitions.jpg

Step 3: Tick all unallocated space then click “OK”.


Step 4: It will go back to the main interface and pending operations are listed. You may redo before clicking “Apply” for final execution.


Of course, it not only enables you to merge unallocated space to system partition in Windows 10, but also lets you merge two drives in Windows 10. Anyway, many advanced features are available in AOMEI Partition Assistant which will help you manage your computer better.