By Emily / Last Updated April 28, 2023

Not enough space for System Reserved partition

I have a Windows 7 machine that I need to upgrade to Windows 10. However, the installation is giving me issues. Finally, I find out the reason, there is not enough space for the System Reserved partition. Does anyone know how to increase System Reserved partition? Any suggestion would be much appreciated. Thank you!

Why increase System Reserved partition in Windows 7/8/10?

A System Reserved partition, a Windows partition that is created when you clean install Windows 7/8/10/11, contains necessary files to boot your computer. If there is not enough space on System Reserved partition, you may fail to upgrade to Windows 10 from Windows 8.1 or Windows 7 with the error message: We couldn’t update the System Reserved partition. It may also come with other errors.

Failed to Install Windows

The System Reserved partition acquires 100 MB space on Windows 7, 350 MB on Windows 8, and 500 MB on Windows 10. Since upgrading to Windows 10 needs more space on the System Reserved partition, Windows 10 will not upgrade unless it detects that the System Reserved partition has enough space.

How to increase System Reserved partition in Windows 7/8/10/11?

Here is a problem, the System Reserved partition can't be extended easily with Disk Management. Whenever you try to extend it in the Disk Management console, you will find that the "Extend Volume..." option is grayed out. To extend the System Reserved partition space, you need to find a professional third-party tool. It is recommended to use AOMEI Partition Assistant Standard.

AOMEI Partition Assistant Standard is a free disk manager which is designed for all editions of Windows 7/8/10/11/Visa/XP. You can increase System Reserved partition easily and securely with the help of AOMEI Partition Assistant. Besides, you can also use it to resize BitLocker partition. Let’s see how to increase System Reserved partition in Windows 7/8/10/11 with detailed steps.

Step 1. Free download this freeware, install and open it.

Download Freeware Win 11/10/8.1/8/7/XP
Secure Download

Step 2. Right-click on a redundant partition and select "Resize/Move Partition" to generate unallocated space. You can select C: drive or the drive after C. (As it only needs 400 MB at most, you can resize partition and generate some free space from C drive to make the System Reserved partition bigger.)

Here we take C: partition for example and our aim is to take some space from C: partition to System Reserved partition.

Resize C Drive

Step 3. In the pop-out "Move and Resize Partition" window, tick the box: I need to move this partition and drag the slider bar from left to right. You can also enter the specific amount of space you want to shrink. After that, click OK.

Move and Resize Partition

Step 4. Then you will go back to the main interface of AOMEI Partition Assistant, and you can see here is unallocated space after System Reserved partition and before the C: drive.

Step 5. Right-click System Reserved partition and select "Resize/Move Partition".

Increase System Reserved partition

Step 6. In the pop-out window, drag the slider bar rightward to extend System Reserved into unallocated space. Then click OK to return to the main interface of AOMEI Partition Assistant.

How to Increase System Reserved Partition

Step 7. Click Apply to execute the process. The program will need to restart your computer to complete these operations under PreOS Mode. To make it easier, you can also use another feature called "Merge Partitions", which allows you to unallocated space, which is areadly on your disk now, into system reserved partition or other partitions that you need to enlarge.

Merge Partitions

Besides, you can use AOMEI Partition Assistant Professional to simply allocate free space from any other partition to System Reserved partition.


After increasing the System Reserved partition, you should be able to upgrade Windows 7 or Windows 8 to Windows 10 or Windows 11 without receiving errors. And after upgrading to the desired Windows, you may find there will be multiple recovery partitions, you can delete the nonfunctional partition to free up some space.  Also, you can use AOMEI Partition Assistant to migrate OS, clone disk, and convert disk between MBR and GPT without losing data, etc.