Windows 10: Recommended Size of EFI Partition V1709

I recently built a machine and have noticed that my EFI partition size is 100MB. I clean installed with V1703 and subsequently upgrade to V1709

Reading the threads (some in forum and some on web) there seems to be a lot of noise that the EFI partition should be 500+ MB.

In this article it says the minimum is 100MB, dated May 2017.

https://docs.microsoft.com/en-us/win...ive-partitions

As the build is new I thought I would address any size issues now rather than later.

Does anyone have a link to a MS technical document that states a recommended EFI size? (not the minimum size)

Thanks

:)

 

Esp.vhdx image of the EFI system disk shows a partition size 4MB shorter than the real disk.

With windows 10 64bit v1709.

In 2 different machines I checked the WindowsImageBackup files and I see that the size of the EFI partition saved in the Esp.vhdx file does not match the size of the partition on the real disk where it came from.

Can somebody explain why it is 4MB shorter in the Esp.vhdx than it is in the real disk ?

1) In one case the EFI partition size on the disk is 100MB, but the size showing on the attached Esp.vhdx is only 96MB

2) Another case the EFI partition size on the disk is 260MB, but the size showing on the attached Esp.vhdx is only 256MB.

The other partition sizes on the real disk and the images match, the difference of 4MB is only on the EFI partition, why ?

Here are the disk manager pictures of the 2 cases. 100MB on disk versus 96MB on the image, 260MB on disk versus 256MB on the image.

Is this related to the restore error 0x80042302 when trying to restore on a new disk ?

1) 512GB SSD on Dell XPS8700









2) 512GB SSD on Lenovo Yoga929

 

Can't install Windows updates.

I tried again, this time using the Windows 10 Upgrade ****'t but still couldn't install 1607. Got error message 0xc1900200. The recommendation was to increase the size of EFI Health partition from 100mb to 250 mb. So I shrunk the Primary partition by 300mb
to free up some unallocated space, then tried to increase the size of the EFI partition by going to action/all tasks/extend partition, but was unable to do so, That option, as well as all other options, was greyed out. So I'm back to square 1.

Any help appreciated. The computer is a Asus M32 system, less than one year old, Core i3 6100 cpu, 4gb RAM and 250gb SSD with 60gb available.

 

The size provided by Microsoft's script in this article is 100mb:
UEFI/GPT-based hard drive partitions | Microsoft Docs

I've had no issues with 100mb EFI system partitions.

 

Thank you NavyLCDR.

That is the same article I posted with minimum.

Are you dual booting anything? Pretty sure you are are as I've seen posting where you have Macrium (I think) at end of your disk.

 

Yes, dual booting Windows 10 Pro and Education on my laptop. On my desktop at home I am booting Windows 10 Pro, Windows 7 Pro, and Windows 7 Home Premium. When you add a different OS to the boot menu which runs from the BCD, it only adds a few lines of text to the BCD and only consumes a few addition bytes - not even 1K more.

According to MiniTool, my EFI System Partition has 29.4 MB used out of 101 MB and that is dual booting - with a third menu option to boot into Kyhi's Recovery Tools from a second installed hard drive.

 

Thanks.

Made by life a whole lot easier. Had a crazy plan developed to resize and moving 16MB MSR was a real issue.

Thanks again.

 

The default size of the EFI partition is now 100 MB.

The size of the EFI partition was chosen by Microsoft as a size that should be able to allow sufficient space for:
languages
fonts
BIOS firmware
BIOS updates
computer manufacturer firmware/software

There are firmware/software that are installed into the the EFI partition instead of the data drive.
Over time the free space within the EFI partition decreases with BIOS updates.
When it comes time to Windows upgrades it will need a certain amount of free space within the EFI partition.

On a custom computer there should not be any problems with a Windows upgrade related to the size of the EFI or MSR partition.

Windows upgrade failures related to EFI or MSR partition free space are more common in non-custom computers that have had multiple bios upgrades or software/firmware installed in the EFI partition.

 

Thanks zbook. Solid technical information.