Best Fix: "We Couldn't Update System Reserved Partition" Windows 10
Well, do you want to know the exact cause(s) for this error or do you know how to clear the very roadblock for successful upgrade? If you haven't got any good idea, please read this post, and we will tell you reason(s), along with 2 solutions which have been proved to work flawlessly.
2 Causes for "Windows 10 Upgrade Couldn't Update System Reserved Partition" Error
After a series of tests and researches we found 2 causes for this error, including:
Cause 1: system reserved partition is full. Microsoft says some third-party anti-virus and security apps write to the system reserved partition, which could fill the partition up.
Cause 2: File system of system reserved partition runs in error.
Now that causes have been found, it should be easy to fix the issue: if the error is caused by low disk space, increase system reserved partition size; if the error occurs due to file system error, fix file system of Windows 7/8.1 system reserved partition instead.
Nevertheless, Windows does not provide users with easy-to-use and effective solutions to do these operations, so users had better employ a free third party partitioning program. Fortunately, MiniTool Partition Wizard Free Edition will bring users great surprise.
How to Quickly Fix "Windows 10 Upgrade Couldn't Update System Reserved Partition" Error
Since most users do not know which is the actual cause for this error, it is very necessary to view and check properties of the system reserved partition at first. MiniTool Partition Wizard shows partition properties clearly.
Please download and install MiniTool Partition Wizard Free Edition on your computer.
Then, run and launch the freeware to get its main interface:
From the screen above we can see the first partition is marked as system reserved, and it is always the one we are looking for.
Nevertheless, there are exceptions. Sometimes it isn't shown as system reserved but with other labels. Let's see the following example.
Here we can see no partition is labeled as system reserved. Well, does it mean there is no such partition on this computer? Of course not.
Actually, users had better check partition status rather than label to distinguish system reserved partition from other partitions, and the partition shown as Active is always the one we are looking for. Therefore, in the screenshot above the partition labeled with RECOVERY is the system reserved partition.
Tip: on GPT disk, this partition is not called system reserved partition but called EFI system partition or ESP:
After the correct partition is found, please view unused space of this partition.
If there is little or no free space left in this partition, "Windows 10 upgrade couldn't update system reserved partition" error is largely caused by low disk space of system reserved partition or ESP. Under this situation, to enlarge the partition is the best solution rather than delete unless files. After all, this partition saves Windows boot files, and mistakenly deleting any important file could make Windows unbootable.
However, if the system reserved partition has much free space, the most probable reason would be file system error. In this case, please try checking and fixing file system of the system reserved partition or EFI system partition.
Of course, you can extend system reserved partition or ESP and fix its file system together since both require simple operations.
Next, let's start fixing the Windows 10 upgrade error.
Increase System Reserved or EFI System Partition Size in Windows 7/8.1
Tip: nowadays, Legacy BIOS + MBR and UEFI + GPT are 2 most commonly seen boot modes on Windows platform. Under different mode operations of extending system reserved partition are little bit different so that we will show detailed steps on both modes.
Extend System Reserved Partition Under Legacy BIOS + MBR Boot Mode
If you are booting Windows from MBR disk, please take the following operations:
Buy MiniTool Partition Wizard so as to create MiniTool Partition Wizard Bootable CD.
Step1: Create a bootable CD/DVD, or USB flash drive. For instructions, please see How to Build Boot CD/DVD Discs and Boot Flash Drive with Bootable Media Builder?
Step 2: Boot computer from MiniTool Partition Wizard Boot Disc.
Step 3: Select the system reserved partition and choose "Extend Partition" feature from the left action panel.
Step 4: Extend the target partition by taking free space from other existing partitions on the same disk and click "OK".
Step 5: Click "Apply" button on the top to perform all changes.
After these steps, increasing space for system reserved partition has been completed. For more details, please see Extend Partition. And then, you should be able to upgrade to Windows 10.
Then, it's time to enlarge EFI system partition on GPT disk.
Enlarge EFI System Partition Under UEFI + GPT Boot Mode:
For users who are running Windows on GPT disk, they can increase EFI system partition (ESP) size by taking the following steps.
Buy MiniTool Partition Wizard so as to create MiniTool Partition Wizard Bootable CD.
Step 1: Create MiniTool Partition Wizard Boot Disc
Step 2: Boot Computer via MiniTool Partition Wizard Boot Disc to Get Partition Layout:
Here the 500MB ESP partition which is marked as Active is the very partition we need to enlarge, and now it has no free space available. But fortunately, we can enlarge it by taking free space from any other existing partitions with recognizable file system (FAT or NTFS) on the same hard disk. For example, we can extend the ESP partition by taking free space from partition C since this partition has 760GB unused space left. Of course, we can also enlarge it by making use of unallocated space if there is such a kind of space.
Step 3: Delete Microsoft Reserved Partition
However, in the case above, if we want to extend the EFI system partition (ESP) by borrowing free space from partition C, we need to delete the 128MB Microsoft Reserved Partition (MSR partition) at first since Partition Wizard can't recognize its file system.
Well then, does it mean users must delete the MSR partition when they plan to enlarge EFI system partition? Of course not. Actually, only when the MSR partition is located between the EFI system partition and the partition we want to take free space from, the 128MB partition should be deleted. If not, the extending process will be stopped. For detailed steps to delete an existing partition, please see Delete Partition.
Tip: deleting the 128MB Microsoft reserved partition does no harm to both data and system, so users can do it without any worries.
Step 4: Enlarge EFI System Partition
Select the EFI system partition and choose "Extend Partition" feature from the left action panel. Next, choose partition C from the drop-down list of "Take Free Space from" and then drag sliding handle to decide how much free space to take. Then, click "OK" to go back to the main interface.
At last, click "Apply" button to make all changes performed.
After all changes are made, try upgrading your Windows 7 or 8.1 to Windows 10 again.
PS. Lots of users have consulted us with the same problem via email, telephone, or online chat, and they finally fixed the error by increasing system reserved partition size of Windows 7 or 8.1, so you can also have a try. It brings no damage to both data and system.
Fix File System of System Reserved Partition in Windows 7/8.1
Step 1: Download and Install MiniTool Partition Wizard Free Edition
To check and fix file system of the system reserved partition in Windows 7/8.1, please download and install MiniTool Partition Wizard Free Edition instead of Boot Disc.
Step 2: Assign a Letter for System Reserved or EFI System Partition
As "Check File System" can only be used when the selected partition has a drive letter, please select the system reserved partition or EFI system partition (ESP) and click "Change Drive Letter" function to get the following screenshot:
Now, please choose an appropriate letter for this partition and click "OK" to go back to the main interface. And then click "Apply" button on the top to make this change performed.
Step 3: Check and Fix File System of System Reserved or EFI System Partition
Reselect the system reserved or EFI system partition and choose "Check File System" feature to get the following window:
Then, choose "Check & fix detected error" since this feature will detect all file system errors and then fix them one after another, and next click "Start" button to start checking and fixing.
If there are file system errors found and fixed, users can try upgrading to Windows 10 again, and this time the "Windows 10 upgrade couldn't update system reserved partition" error shouldn't emerge.