How can I create a larger EFI partition during a fresh Windows 11 Pro install

StonyCreeker · Jul 7, 2025

Thank you all for the responses. I'll try to answer as many of your questions as I can.

@Megahertz, I believe the reason is as @garlin said. The OEM expects it to be that size for their own reasons. Their reasons could be what @hsehestedt noted:

Normally 100 MB is just fine, however, the EFI partition is formatted as FAT32 and on advanced format native 4k drives the minimum partition size for FAT32 is - you guessed correctly - 260 MB. So, by using a 260 MB EFI partition you guarantee compatibility with ALL systems.

@garlin, yes, that is exactly what I would like to end up with.

The Lenovo defaults for these systems with 256GB drives are:
EFI: 260MB
MSR: 16MB
Primary: 236 GB
Recovery: 2000MB

To achieve this with your code, I would need to change the "shrink minimum=800" to "shrink minimum=2000", yes?
Just to absolutely clear, if I were to use your code, I need to remove the ==> parts. I assume those are just there as explanations.

@hsehestedt, thank you for the well documented code. I do understand it and I do know how to find the drive letter for the Windows media.

@Megahertz

Why not format the original Win partition and apply the Win VLSC image on the partition. This will keep the original EFI and the Tools partition that has the diagnostic and maintenance tools.

That would be an excellent idea and would eliminate all of this mess if it works as you describe. I haven't considered it because the boss who taught me how to do this said that any partitions I left on the drive would just get duplicated during the installation. I have seen instances where we've ended up with extra partitions (particularly recovery partitions, I believe).
You mention formatting the original Win partition then applying the image to it. Does that partition need to be formatted or will it work just as well on unformatted space?
@zbook, I have no idea what it wants to install in the EFI partition.
Here is the error I get:

SYS1231 Website Download BIOS Update Error Message.webp

Lenovo support are the ones who told me this was caused by having too small of an EFI partition.
I updated my "My Computers" section.

NOTE: One thing that all of you have taught me is that the Diskpart clean command leaves you with an MBR disk by default. I had not realized this and will now be more careful about converting it to GPT before going any further.

Considering all of your inputs, I think that I will try two things:

On the next new system I work on, I will try just deleting the Windows partition, formatting it, then selecting that partition for the installation.
On the next "used" system that needs to be reimaged, I will try creating an new image using an autounattended.xml file created with @garlin's code in Schneegan's autounattended generator.

Thanks again for all your help!

zbook · Jul 7, 2025

The Windows 10 and 11 clean install default EFI partition size is 100 MB.

How come a larger size is needed?

What does Lenovo support plan to install in the EFI partition?

garlin · Jul 7, 2025

StonyCreeker said:
@garlin, yes, that is exactly what I would like to end up with.

The Lenovo defaults for these systems with 256GB drives are:
EFI: 260MB
MSR: 16MB
Primary: 236 GB
Recovery: 2000MB

To achieve this with your code, I would need to change the "shrink minimum=800" to "shrink minimum=2000", yes?
Just to absolutely clear, if I were to use your code, I need to remove the ==> parts. I assume those are just there as explanations.

The quoted diskpart was for demonstration purposes.

If we return to the unattended file:

Code:

<?xml version="1.0" encoding="utf-8"?>
<unattend xmlns="urn:schemas-microsoft-com:unattend">
    <settings pass="windowsPE">
        <component name="Microsoft-Windows-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
            <ImageInstall>
                <OSImage>
                    <InstallTo>
                        <DiskID>0</DiskID>
                        <PartitionID>3</PartitionID>
                    </InstallTo>
                </OSImage>
            </ImageInstall>
            <RunSynchronous>
                <RunSynchronousCommand wcm:action="add">
                    <Order>1</Order>
                    <Path>cmd /c (for %a in ("sel dis 0" "cle" "con gpt" "cre par efi size=260" "for quick fs=fat32" "cre par msr size=16" "cre par pri" "shr minimum=2000" "for quick fs=ntfs") do @echo %~a) &gt; X:\UEFI.txt</Path>
                </RunSynchronousCommand>
                <RunSynchronousCommand wcm:action="add">
                    <Order>2</Order>
                    <Path>cmd /c (for %a in ("cre par pri" "for quick fs=ntfs" "set id=de94bba4-06d1-4d40-a16a-bfd50179d6ac" "gpt attributes=0x8000000000000001") do @echo %~a) &gt;&gt; X:\UEFI.txt &amp; diskpart /s X:\UEFI.txt</Path>
                </RunSynchronousCommand>
            </RunSynchronous>
            <UserData>
                <ProductKey>
                    <Key></Key>
                </ProductKey>
            </UserData>
        </component>
    </settings>
</unattend>

The magic numbers are EFI (260), MSR (16), Windows (whatever's left), and Recovery (2000).
When you follow the recommended layout, all you need to do is to change EFI and Recovery. Almost everyone leaves MSR at the default 16.

Recovery partition sizes are trending up for enterprise PC's for two reasons:

1. MS will enable BitLocker or basic Device Encryption on a clean install, since most PC's now have TPM 2.0 or later. Therefore more emphasis is placed on a working Recovery environment so you can deal with BitLocker repair issues.

2. Recovery rolls over the same core drivers installed in Windows. Some of these (like NVIDIA, Intel iGPU, Realtek) are fairly bloated and carry over hefty DLL's along with the base driver. Sizing up to 2 GB future-proofs the Recovery partition from having to be resized at a later date.

SIW2 · Jul 7, 2025

@garlin

shrink minimum=800

why minimum instead of desired

garlin · Jul 7, 2025

zbook said:
The Windows 10 and 11 clean install default EFI partition size is 100 MB.

How come a larger size is needed?

What does Lenovo support plan to install in the EFI partition?

Since you're not supporting an enterprise, here's the scoop:
OSD Partition Setup, Mike Terrill Edition (The Optimized Way). – GARYTOWN ConfigMgr Blog

zbook · Jul 7, 2025

HP is no longer causing this problem in the 2018 link:

OSD Partition Setup, Mike Terrill Edition (The Optimized Way). – GARYTOWN ConfigMgr Blog

garytown.com

Code:

HP requires minimum of 360 & MS requires minimum 200 – all the more reason to do 496.  Remember, these are minimum requirements, would you ever run Windows on minimum hardware requirements? No way, the experience would be horrible!  Do yourself a favor and go much larger!

HP Commercial Notebooks and Desktop PCs – Insufficient EFI Partition Size Prevents BIOS Update or Auto-Recovery | HP® Support
UEFI/GPT-based hard drive partitions | Microsoft Learn
Microsoft process for trying to clear up a little space on the system Partition

“We couldn’t update system reserved partition” error installing Windows 10 – Microsoft Support
Posted on GARYTOWN.COM

garlin · Jul 7, 2025

SIW2 said:
why minimum instead of desired

OP is working in the enterprise space. If you can't shrink by a requested amount, it should error out and not just give you less than requested. Granted we're technically not catching the exit condition from diskpart, to know if it succeeded or not. But the principle is the same.

If you're like @pseymour, there's plenty of IT war stories where something "close enough" causes an unforeseen problem down the road. When you scale up to hundreds, thousands, or ten thousand machines, the cost of a tiny error and the time to fix it in a production environment is very expensive.

When you mess up a home computer, it's done on your time and not breaking the business' time.

SIW2 · Jul 7, 2025

I usually do 300mb esp because diskgenius suggests it. Handy to have a bit of space so I can fool around in there.

zbook · Jul 7, 2025

Dell and Lenovo may have links were files are installed in the EFI partition.

This is from the Microsoft GPT link:

System partition:

This partition is managed by the operating system, and should not contain any other files, including Windows RE tools.

SIW2 · Jul 7, 2025

Megahertz · Jul 7, 2025

StonyCreeker said:
@Megahertz

That would be an excellent idea and would eliminate all of this mess if it works as you describe. I haven't considered it because the boss who taught me how to do this said that any partitions I left on the drive would just get duplicated during the installation. I have seen instances where we've ended up with extra partitions (particularly recovery partitions, I believe).
You mention formatting the original Win partition then applying the image to it. Does that partition need to be formatted or will it work just as well on unformatted space?

Considering all of your inputs, I think that I will try two things:

On the next new system I work on, I will try just deleting the Windows partition, formatting it, then selecting that partition for the installation.

On the next "used" system that needs to be reimaged, I will try creating an new image using an autounattended.xml file created with @garlin's code in Schneegan's autounattended generator.

Thanks again for all your help!

@Megahertz
Why not format the original Win partition and apply the Win VLSC image on the partition. This will keep the original EFI and the Tools partition that has the diagnostic and maintenance tools.

I said to format the C: partition and apply the Win VLSC image. It is completly different from install to an unallocated space.
You have to use DISM to extract the Win VLSC files and folders from the Install.wim and put them on the partition.
@SIW2 can help you with the details on how to apply an image to a partition.

Megahertz · Jul 8, 2025

Let's see what do you have on the Win VLSC USB installation drive.
On any computer with the Win VLSC USB installation drive on a USB port, open a CMD window as administrator and type:
W: (replace W with the Win VLSC USB installation drive letter)
cd \sources
dir install.* (take note if you have Install.wim or install.esd)

dism /Get-WimInfo /WimFile:W:\Sources\install.wim ( For install,wim. Replace W with the Win VLSC USB installation drive letter)
or
dism /Get-WimInfo /WimFile:W:\Sources\install.esd ( For install,esd. Replace W with the Win VLSC USB installation drive letter)

Witch index number you want to apply the image?

Below is the result for a regular Win 11 24h2 installation drive on G:

StonyCreeker · Jul 8, 2025

@garlin

If we return to the unattended file:

Code:

<?xml version="1.0" encoding="utf-8"?>
<unattend xmlns="urn:schemas-microsoft-com:unattend">
    <settings pass="windowsPE">
        <component name="Microsoft-Windows-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
            <ImageInstall>
                <OSImage>
                    <InstallTo>
                        <DiskID>0</DiskID>
                        <PartitionID>3</PartitionID>
                    </InstallTo>
                </OSImage>
            </ImageInstall>
            <RunSynchronous>
                <RunSynchronousCommand wcm:action="add">
                    <Order>1</Order>
                    <Path>cmd /c (for %a in ("sel dis 0" "cle" "con gpt" "cre par efi size=260" "for quick fs=fat32" "cre par msr size=16" "cre par pri" "shr minimum=2000" "for quick fs=ntfs") do @echo %~a) &gt; X:\UEFI.txt</Path>
                </RunSynchronousCommand>
                <RunSynchronousCommand wcm:action="add">
                    <Order>2</Order>
                    <Path>cmd /c (for %a in ("cre par pri" "for quick fs=ntfs" "set id=de94bba4-06d1-4d40-a16a-bfd50179d6ac" "gpt attributes=0x8000000000000001") do @echo %~a) &gt;&gt; X:\UEFI.txt &amp; diskpart /s X:\UEFI.txt</Path>
                </RunSynchronousCommand>
            </RunSynchronous>
            <UserData>
                <ProductKey>
                    <Key></Key>
                </ProductKey>
            </UserData>
        </component>
    </settings>
</unattend>

If I understand you correctly, the code above is the entire autounattend.xml file that I need to make my partitions during installation.
And all I need to do with the file is make sure it's named autounattend.xml and in the root directory of my Windows installation USB stick. Windows will take it from there once I boot from the stick. And the correct file name is autounattend.xml not autounattended.xml. Is all of that correct?

@Megahertz

I'm sorry for the misunderstanding. I've never installed Windows by any method other than standard installation or by installing a custom image captured from a system that had been manually set up to be exactly the way we want all of our computer to be.

Below is the result of running the command you requested on the install.WIM file. We want index number 5. Note that we make our bootable sticks with the latest version of Rufus using the "Remove requirement for an online Microsoft account" option since we initially create two local accounts and prefer not to be pestered to login with a Microsoft account until we want to.

Do you have recommendations based on this information?

Based on the latest discussion, I've changed my plan. Now my first attempt will be to use the autounattend.xml file @garlin kindly made for me. If I can get that to work, I'll expand it by creating a file with Schneegan's autounattend generator, then dissecting it to understand what each part is designed to do. I think that will help me learn more about this process.

Thanks again for all your help everyone.

garlin · Jul 8, 2025

StonyCreeker said:
And the correct file name is autounattend.xml not autounattended.xml. Is all of that correct?

autounattend.xml
The alternative form, if copied to a different folder path, is unattended.xml

StonyCreeker said:
Based on the latest discussion, I've changed my plan. Now my first attempt will be to use the autounattend.xml file @garlin kindly made for me. If I can get that to work, I'll expand it by creating a file with Schneegan's autounattend generator, then dissecting it to understand what each part is designed to do. I think that will help me learn more about this process.

If you want to bypass the MS Account requirement, you can add those lines too.
1. Repartition the disk.
2. Install image index 5 to disk 0, partition 3.
3. Bypass the MS Account requirement.

Schneegan's can perform the above tasks (if you copy the list of diskpart commands in the diskpart webform box).

Code:

<?xml version="1.0" encoding="utf-8"?>
<unattend xmlns="urn:schemas-microsoft-com:unattend">
    <settings pass="specialize">
        <component name="Microsoft-Windows-Deployment" processorArchitecture="amd64" language="neutral" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" publicKeyToken="31bf3856ad364e35" versionScope="nonSxS">
            <RunSynchronous>
                <RunSynchronousCommand wcm:action="add">
                    <Order>1</Order>
                    <Path>reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\OOBE /v BypassNRO /t REG_DWORD /d 1 /f</Path>
                </RunSynchronousCommand>
            </RunSynchronous>
        </component>
    </settings>
    <settings pass="windowsPE">
        <component name="Microsoft-Windows-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
            <RunSynchronous>
                <RunSynchronousCommand wcm:action="add">
                    <Order>1</Order>
                    <Path>cmd /c (for %a in ("sel dis 0" "cle" "con gpt" "cre par efi size=260" "for quick fs=fat32" "cre par msr size=16" "cre par pri" "shr minimum=2000" "for quick fs=ntfs") do @echo %~a) &gt; X:\UEFI.txt</Path>
                </RunSynchronousCommand>
                <RunSynchronousCommand wcm:action="add">
                    <Order>2</Order>
                    <Path>cmd /c (for %a in ("cre par pri" "for quick fs=ntfs" "set id=de94bba4-06d1-4d40-a16a-bfd50179d6ac" "gpt attributes=0x8000000000000001") do @echo %~a) &gt;&gt; X:\UEFI.txt &amp; diskpart /s X:\UEFI.txt</Path>
                </RunSynchronousCommand>
            </RunSynchronous>
            <ImageInstall>
                <OSImage>
                    <WillShowUI>OnError</WillShowUI>
                    <InstallFrom>
                        <MetaData wcm:action="add">
                            <Key>/IMAGE/INDEX</Key>
                            <Value>5</Value>
                        </MetaData>
                    </InstallFrom>
                    <InstallTo>
                        <DiskID>0</DiskID>
                        <PartitionID>3</PartitionID>
                    </InstallTo>
                </OSImage>
            </ImageInstall>
            <UserData>
                <AcceptEula>true</AcceptEula>
                <ProductKey>
                    <Key></Key>
                </ProductKey>
            </UserData>
        </component>
    </settings>
</unattend>

Megahertz · Jul 8, 2025

This is the procedure to apply the Win 11 pro (index 5) to the existing OEM drive.
Does the Win VLSC USB installation drive created with Rufus has two partitions? If it does, identify the one that has \sources\install.wim.
I will assume you're booting from the Win VLSC USB installation drive.

1) Format the OEM windows partition

Insert the Win VLSC USB installation drive and boot from it as UEFI.
- At the Windows Setup screen, press Shift+F10 simultaneously to open a command line prompt and type:
Diskpart
list disk (it will list all drives. Identify the main drive number)
sel disk n (replace n by the main drive number obtained with list disk)
list vol (take note of the Windows partition letter W (It may not be C:) and Win VLSC USB installation drive letter (K) that has Install.wim)
sel vol W (replace W by the windows volume letter obtained with list vol above)
format fs=ntfs quick
assign letter=W (replace W by the windows volume letter obtained with list vol above)
exit (to exit diskpart)

2)Applying the the Win 11 pro (index 5) to the partition

dism /Apply-Image /ImageFile:K:\Sources\install.wim /index:5 /ApplyDir:W:\
(replace K by the Win VLSC USB installation drive letter and W by the windows volume letter obtained with list vol above)
exit (to exit CMD window)
close Windows Setup window.
- Shut down

3) Finish installing Win 11 pro (index 5)

- Remove the Win Win VLSC USB installation drive
- Boot. It will begin to install windows from second phase.
- When you apply the image, you don't do the normal install procedure so the option to local account on Rufus wont be applied.
Use step 13 on Brink tutorial

Clean Install Windows 11

This tutorial will show you step by step on how to clean install Windows 11 at boot on your PC with or without an Internet connection and setup with a local account or Microsoft account. Windows 11 has all the power and security of Windows 10 with a redesigned and refreshed look. It also comes...

www.elevenforum.com

4) Install Office and other software s and create a drive image template to apply to other computers (optional).

As I already mentioned, instead of doing the process above to each computer, once the first drive with the applied Win VLSC Pro image reaches the point to create a user (OOBE) you can enter Audit mode and Install Office and other software s. Once done you go back to OOBE, shut down and create a drive image (with Macrium, Aomei or other drive image creator software) and apply this image to the other computers.
When you start a computer with this template, Windows, Office etc is already installed and you only have to create the local user profile. Much, much faster then configure computer by computer.

zbook · Jul 8, 2025

Food for thought:

In Ten Forums many members made free backup images using Macrium Reflect:

Backup and Restore with Macrium Reflect

How to Create and Restore a System Image Backup with Macrium Reflect

www.tenforums.com

The software may no longer be free.

One of its features was the ability to restore only the C: partition.

Check its current costs and features to see whether the partitions can be created using command line followed by a C: partition restoration.

There were one or more threads that @NavyLCDR had created a Windows drive in TF.

It may have been MBR or GPT or both.

He may have ideas for the thread title and doublecheck these commands:

Boot using any Windows Media Creation Tool (MCT)(Windows iso)

Open command prompt > type:

diskpart

lis dis

sel dis W (change W to the planned new Windows drive)

clean

convert gpt

create partition efi size=260

format quick fs=fat32 label="EFI System"

create partition msr size=16

create partition primary size=236000

format quick fs=ntfs label="Windows"

create partition primary size=2000

format quick fs=ntfs label="Recovery"

set id="de94bba4-06d1-4d40-a16a-bfd50179d6ac"

gpt attributes =0x8000000000000001

exit

hsehestedt · Jul 9, 2025

garlin said:
The alternative form, if copied to a different folder path, is unattended.xml

Correction: The alternative is unattend.xml without the "ed" at the end.

hsehestedt · Jul 9, 2025

StonyCreeker said:
Based on the latest discussion, I've changed my plan. Now my first attempt will be to use the autounattend.xml file @garlin kindly made for me. If I can get that to work, I'll expand it by creating a file with Schneegan's autounattend generator, then dissecting it to understand what each part is designed to do. I think that will help me learn more about this process.

If I may make a suggestion:

Try taking a look at the tutorial linked to below on TenForums. In particular, take note of section 3 and 4 of that tutorial. Those two sections describe in detail what every one of the more common entries in both the autounattend.xml and the unattend.xml files are. At first glance that tutorial may seem just a little bit daunting because it is rather long. But that is mainly because there are so many screenshots, and everything is explained in such great detail. I really strongly suggest looking at it. My entire foundation of unattended installations stems from that very tutorial.

Just one other thing to note about that tutorial: That tutorial makes use of both an autounintend.xml and an unattend.xml file. This is done when setting up a reference system that you then later image to replace the standard image that comes on the Windows installation media. You don't need to worry about those details for the moment. Just know that if you did want to adapt that tutorial to use just a single autounattend.xml answer file It is extremely easy to modify that tutorial to do that. If that is something you are interested in knowing more about I can very easily share that information with you. But for now, the main idea is that the two sections, Section 3 and Section 4, will give you a good understanding of what most of the settings that you will be using do.

Create media for automated unattended install of Windows 10

How to create install media for completely automated unattended install of Windows 10

www.tenforums.com

Topgundcp · Jul 9, 2025

The Windows setup goes through several phases, with the last one being the Out-of-Box Experience (OOBE)
If you wish, you can try my suggestion using a batch file as shown below:

1. Phase 1: Download the attachment containing a file: InstallGPT.bat, copy to the root folder of the Installation USB.
This batch file will create partitions layout then extract Windows System Files to partition 3, setup boot file (BCD)
2. Phase 2 (OOBE) The Installation media created with Rufus: Under Sources\$OEM$\$$\Panther. There's a file: unattend.xml, copy to the root folder of the Installation Media. This file will add few registry entries and create a Local User.
3. Boot up the Installation Media. On first screen, press SHIFT+F10 to display Command Prompt and type: echo list Vol | diskpart
and identify the drive letter of the Installation media, navigate to it then run: installGPT.bat
4. once done, reboot. Depend on how fast your PC is, it should not take more than 15 minutes to complete installation

NOTE: The default set in the Batch file are shown in red square, edit and make any change you wish.
This procedure can also be run on any PC both online (Windows Running) to install on an external/internal SSD/HD/Nvme,
once done, connect to the target PC. or Offline (Boot from Installation USB)
IMPORTANT: Make sure to select correct target disk #

How can I create a larger EFI partition during a fresh Windows 11 Pro install

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