By AOMEI / Last Updated October 18, 2019

The Symptom

When you upgrade to Windows 10 from Windows 8.1 or Windows 7, the upgrade may fail with the following error message: "We couldn't update the system reserved partition". It may also come with error code: 0x800F0922 or other errors.

Couldnt Update System Reserved Partition

The Cause

This Windows 10 upgrade error is usually caused by insufficient space on the System Reserved partition. When you install Windows to a partitioned MBR disk, Windows will create an additional partition without drive letter labeled as System Reserved, which stores important boot files and normally locates before the system partition (often known as C: drive).

On Windows 7, it often takes 100MB disk space, 350MB on Windows 8, and 500MB 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.

If you fresh install Windows 10 to a specific partition, you won't receive this error. By the way, the System Reserved partition first appearance was on Windows 7, so you won't have this error on previous versions of Windows.

The Solution

To solve this problem of being unable to update System Reserved partition, you can increase the size of System Reserved partition using third party free partition software like AOMEI Partition Assistant Standard, which can manage your disks and partitions without data loss.

1. Download this freeware. Install and launch it.

2. Right-click on the partition you want to shrink and select "Resize Partition". You can select C: drive or the drive after it. Here we take D: partition for example, and our aim is to take some space from D: partition and add it to System Reserved partition.

Resize D

3. In the pop-out "Move and Resize Partition" window, drag the slider bar from left to right. You can also enter the specific amount of space you want to shrink.

Shrink D

4. Right-click C drive and select "Resize Partition". Drag the C: drive rightward to make the unallocated space next to System Reserved partition.

Resize C

Move C

5. Right-click System Reserved partition and select "Resize Partition". In the pop-out window, drag the slider bar rightward to extend System Reserved into unallocated space.


6. Click Apply to execute the process. The program will need to restart your computer to complete these operations under PreOS Mode. You can also create a bootable media with AOMEI Partition Assistant to complete the process.


Then you should be able to upgrade Windows 7 or Windows 8 to Windows 10 without receiving "we couldn't update the system reserved partition" error. After upgrading to Windows 10, you can still use AOMEI Partition Assistant to migrate OS, copy disk, and convert disk between MBR and GPT, etc as it supports Windows 10/8.1/8/7/XP/Vista.

If you want this to be even easier done, you can use AOMEI Partition Assistant Professional to simply allocate free space from any other partition to system reserved partition.