How to fix issues with installing Windows 11 25H2 regarding the error message, "We couldn't update the system reserved partition."

Question

Windows 11 25H2 fails to install over the past months. The error message that returns reads, "We couldn't update the system reserved partition." I do not have 3p antivirus running. I am on version 24H2 (OS Build 26100 4484). The system is an HP Elitebook 860. It seems I have tried several recommended remedies (i.e., removed all folders/files under SoftwareDistribution, fix issues/reinstall, etc), but to no avail. It seems to me that I have to extend the system reserved partition manually, but I don't know how to do that and get back to normal after the install is finished. Please advise on a solution. Thank you

Answer 1

Windows has no way of extending a Windows 11 EFI System Partition. It's protected, formatted FAT32 and by default followed by Microsoft Reserved.

You need to use a third party partitioning tool like AOMEI Partition Assistant. Also see

https://support.microsoft.com/en-us/topic/-we-couldn-t-update-system-reserved-partition-error-installing-windows-10-46865f3f-37bb-4c51-c69f-07271b6672ac

https://www.winhelponline.com/blog/0xc1900201-windows-feature-update/