By AOMEI / Last Updated February 25, 2020

As we all know, C drive is usually used to install system, and nearly all applications are put on it. Therefore, as time goes by, an increasing number of files are set on system drive. As a result, C drive is frequently out of space. Then, if we do nothing about it, it will bring many problems to us, such as slow operation and fails to execute some orders. So, what should we do? Increase C drive’s room by adding free space to it! Besides, we will probably concern data loss during our adding free space to C partition. At this point, a partition software is needed. AOMEI Partition Assistant (Professional Edition) is a great choice to help us with this.

AOMEI Partition Assistant is a kind of software which can help us to deal with many problems about partitions and disks. Here, professional edition of AOMEI Partition Assistant will be introduced in details. AOMEI Partition Assistant (Professional Edition) has plenty of functions and properties; some essential ones are listed as follows:

Operating systems support:

  • Windows 8.1

  • Windows 8

  • Windows 7

  • Windows XP

  • Windows Vista

  • Windows 2000

  • (all editions, 32/64-bit)


  • Resize partition

  • Move partition

  • Create partition

  • Delete partition

  • Copy partition

  • Merge partition

  • Copy disk

  • Allocate free space from one partition to another

  • More...

Before start the operations, you would better close all other running programs; otherwise, you have to perform in PreOS Mode. With Partition Assistant, you can easily add free space to C drive.


1. Start AOMEI Partition Assistant (professional edition) and then you can see all the partitions on the disk;

2. Usually, you can right click a drive which has much free space and choose “Allocate Free Space” to give the free space to c partition;

Allocate Free Space

3. Enter a volume (no more than the volume of the free space of the source drive), and choose system drive as the destination drive. Referring to the following screenshot, you can enter a value, then the program will allocate the free space of 76.07 GB from D: to C: drive.

Choose C Drive

4. Click “OK” in the window showed above and it will go back to the main interface of Partition Assistant. At this moment, you can see the final result predicted by Partition Assistant.

5. The operations will take effect only after you: click “Apply” in the tool bar and then do as the guides.

Apply Your Operation

If you do not want to buy Partition Assistant Professional edition, still, you can complete “Add free space to C drive” by taking advantage of the free edition of AOMEI Partition Assistant. You can rely on “Extend Partition Wizard” to enlarge drive C easily with the free edition!