We couldn't update the system reserved partition

In Command Prompt (Run as Administrator):

1. Mount the System partition to Y:

mountvol y: /s

2. Switch to the Y drive:

y:

3. Go to the Fonts folder:

cd EFI\Microsoft\Boot\Fonts

4. Delete the files:

del *.*

When prompted, type Y to confirm.

5. Verify the space:

dir

Check the last line showing "X bytes free".

Voila — space freed on the system partition.

See my post (fix) on techcommunity.microsoft.com - Windows 11 not updating to Windows 11 Insider Preview Feature Update (26220.7051) | Microsoft Community Hub

🤗

The free space is not enough in the reserved partition. You need to expand the partition or delete fonts from the partition.

Usually, this kind of error occurs because the system reserved partition (where boot configuration data is stored) is too small or needs to be updated to accommodate the new build. Sometimes, the update process just assumes everything is fine without letting you know if, say, there’s not enough space or if there's a configuration issue. The whole "screen won't help" thing can be really annoying when you're just trying to get everything up to date.

Hello,

It seems you're upgrading to Version 24H2, as there were reports of this error being seen before the upgrade.

See if this fix helps you: 

https://www.kapilarya.com/fix-we-couldnt-update-system-reserved-partition-in-windows-11

Let us know if this helps! 

Note: Included link in this reply refers to blog post by a trusted Microsoft MVP.