How to Resize Partition with AOMEI Partition Assistant?

November 1, 2022

What is partition resizing? How to resize a partition? Resizing partition includes extending partition and shrinking partition. With the help of AOMEI Partition Assistant you could resize partition accurately and easily.

Why do you need to resize partition?

Resizing partition means to change the size of a partition as you like, either extend it or shrink it. But when you shrink a partition, you can at most shrink it to the size of its used space so that you can use the partitions with more flexibility. For example, you can store applications or files on any one of the partitions. If the partition is running out of space, you can extend it with the space shrunk from other partitions. Besides, you can create new partition with the room get from other partitions.

Here are several situations in which you would like to resize partition:

When you buy a new laptop or PC, it may have been pre-installed with a system and come with a big C drive but small data partitions, or a small C drive but large data partitions. No matter which one it is, you will find it cannot make full use of disk space.
When the computer has been used for a long time, you may have encountered the message: the system drive is running out of space.
If Windows 10 upgrade failed with error “Couldn’t update system reserved partition”, the most likely cause is the system resvered partition is too small. Then you can extend system reserved partition.

For example, once when I was downloading a player online, following the installation steps without setting the destination, a message came saying that my c disk has not enough space to install the application. Thus, I have to either reset the destination or give up my intention. Therefore, later, I was used to set d or f partition as the destination to avoid such problem following the advice of my friends.

I know I can extend my c drive with Windows self-contained function but I didn’t know how for it seems very difficult. Being neither a computer professional nor a computer lover, I’m usually been caught by problems. It is extremely annoying! But now, I’m not troubled by such problems anymore with AOMEI Partition Assistant Professional. It helps me manage my disks very well with its intuitive interface and simple steps. By the way, it is compatible with Windows 10, Windows 8/8.1, and Windows 7.

Before you do

Check the partitions you want to resize and make sure there is no error(It doesn't matter whether the target drive is an encrypted partition or not).
Do not forcibly terminate the tasks or cut off the power or you might lose your data.
Close all running applications on the partitions you want to resize.
More detailed information, you could view the tutorial “How to Safely Partition?”

Resize partition with Partition Assistant

Case 1: Extend Partition

To extend partition means increase partition size; you should notice two points below:
There must be an unallocated space locating on the same hard disk as the partition you want to extend. If there's no unallocated space, you could shrink other partition to generate the unallocated space.
The unallocated space should be adjacent to the partition you want to extend, no matter it is before the target partition or behind it. If not, you could use the feature "Move Partition" to adjust the position of it.
Step 1. Install and launch AOMEI Partition Assistant. In the main console you could view the whole partition configuration. In this demonstrator, there is an unallocated space behind C drive. Then, right-click the partition (here is C drive) you want to extend and select "Resize Partition".

Resize C Drive

Step 2. In the pop-up window, position the mouse pointer on the right border of the partition and drag the border rightwards to extend partition. Then click "OK". (If there's no unallocated space beside the partition, you could not drag the border).

Extend C Drive

Step 3. Then it will back to main console and you could preview the partition be extended. Click the "Apply" on the toolbar to commit the operation.

Apply Extend C Partition

AOMEI Partition Assistant also allows you to extend a partition even without unallocated space or contiguous unallocated space, please refer to how to allocate free space, how to use extend partition wizard or how to merge partitions.
The Merge partitions feature will not work on system reserved partition. If you want to extend system reserved partition, you can Move the unallocated space to the right side of the system reserved partition and then select Resize Partition.

Case 2: Shrink Partition

Shrinking partition could help you release some unused space from one partition and get some unallocated space. After that, you could make new partitions and/or increase other partition size with the unallocated space.
Step 1. Install and launch AOMEI Partition Assistant. In the main console you could view the whole partition configuration. Then, right-click the partition (here is D) which you want to shrink and select "Resize Partition".

Resize D Partition

Step 2. In the pop-up window, position the mouse pointer on either border of the partition and drag the border rightwards or leftwards to shrink partition. Then click "OK".

Shrink D Partition

Step 3. Then it will go back to main console, and you could preview the unallocated space beside the partition. Click the "Apply" on the toolbar to commit the operation.

Apply Resize D Partition


  • The partition shrinking operation will be performed under PreOS Mode and your computer will reboot when:
  • Shrink system and/or boot partition.
  • Shrink a partition on which the page file or AOMEI Partition Assistant installation file is on.
  • Shrink a partition where applications are running. AOMEI Partition Assistant will suggest you close them or perform partition shrinking operation under PreOS Mode.