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

Ghot · Sep 13, 2025

JLMPostNet said:
Great topic.

I gave you ten points, just for filling out your computer specs.

gunrunnerjohn · Sep 13, 2025

FWIW, I always try to have a truly blank disk for a new Windows install to make sure things go as planned. That way I get to decide what happens not an automated procedure that might now do what I'd like to happen.

Also, if you have a system with NVMe and SATA drives, the SATA drives are frequently the lower numbered drives. Obviously, most folks want the Windows install on one of the NVMe drives and not the much slower SATA drives. One reason for removing any drive you don't want Windows to install on... :think:

hsehestedt · Sep 13, 2025

gunrunnerjohn said:
Also, if you have a system with NVMe and SATA drives, the SATA drives are frequently the lower numbered drives.

That is precisely the case for me on several systems. But it's super easy to work around so I never bother to disconnect any other drives.

gunrunnerjohn · Sep 13, 2025

hsehestedt said:
That is precisely the case for me on several systems. But it's super easy to work around so I never bother to disconnect any other drives.

True, but we're talking about people that don't realize that happens.

hsehestedt · Sep 13, 2025

gunrunnerjohn said:
True, but we're talking about people that don't realize that happens.

Good point.

BrianInEngland · Sep 13, 2025

Not been following this thread but I did a clean install of 25H2 using the MS ISO, it created a 200MB EFI partition

Celery · Sep 13, 2025

BrianInEngland said:
Not been following this thread but I did a clean install of 25H2 using the MS ISO, it created a 200MB EFI partition

Not been following this thread but if you download the latest version (Jun 26, 2025), 24H2 will also create a 200MB EFI partition.

"Currently 4349 is only available via MCT and not the direct download."

Option One

Download Latest Windows 11 64-bit ISO using Media Creation Tool (MCT)

This will be for a Windows 11 Version 24H2 build 26100.4349 ISO file with install.esd.

garlin · Sep 13, 2025

Current guidance for OEM's is 260 MB.

But HP and Dell users should strongly consider 400 MB because of the way those vendors cache UEFI firmware files in the EFI partition to handle BIOS updates. Other vendors don't do this, so 200-260 MB is probably fine.

BrianInEngland · Sep 13, 2025

aubergine said:
Not been following this thread but if you download the latest version (Jun 26, 2025), 24H2 will also create a 200MB EFI partition.

"Currently 4349 is only available via MCT and not the direct download."

200 is the new 100 I guess

zbook · Sep 13, 2025

BrianInEngland said:
200 is the new 100 I guess

Then that's catchup to this link dated 02/10/2023:

UEFI/GPT-based hard drive partitions

learn.microsoft.com

""The minimum size of this partition is 200 MB, and must be formatted using the FAT32 file format.""

In contrast this remained 100 mb: (11/30/2021)

BIOS/MBR-based hard drive partitions

learn.microsoft.com

""The minimum size of this partition is 100 MB.""

BrianInEngland · Sep 13, 2025

zbook said:
Then that's catchup to this link dated 02/10/2023:

UEFI/GPT-based hard drive partitions

UEFI/GPT-based hard drive partitions

learn.microsoft.com

""The minimum size of this partition is 200 MB, and must be formatted using the FAT32 file format.""

In contrast this remained 100 mb: (11/30/2021)

BIOS/MBR-based hard drive partitions

BIOS/MBR-based hard drive partitions

learn.microsoft.com

""The minimum size of this partition is 100 MB.""

I did a clean install of 26100.1742 using the MS ISO in July, it created a 100MB EFI partition

zbook · Sep 13, 2025

As garlin commented in post #48 some computer manufacturers install firmware / software into the EFI partition.

This reduces the free space that is needed during upgrades.

Years ago I'd clean installed Windows 10 > installed HP firmware / software > had an upgrade failure > contacted HP support > they provided commands to remove their firmware / software from the EFI partition > successful upgrade > HP reported that they no longer install their HP UEFI hardware diagnostics in the EFI partition

(This method is another method that had prevented Windows upgrades. It would not stop the upgrade attempts but all upgrades had failed with the error message " we couldn't upgrade the system reserved partition"). Then after more than five years Microsoft fixed the upgrade where an automatic upgrade worked and no longer found insufficient free space.)

Dell and Lenovo still appear to be installing firmware / software into the EFI partition.
HP appears to no longer use the EFI partition for firmware / software besides BIOS upgrades.

gunrunnerjohn · Sep 13, 2025

I installed four computers starting in March through July, all got 100MB EFI partitions by default.

BrianInEngland · Sep 14, 2025

aubergine said:
Not been following this thread but if you download the latest version (Jun 26, 2025), 24H2 will also create a 200MB EFI partition.

"Currently 4349 is only available via MCT and not the direct download."

Interesting, could this be why I had this problem recently? Doing a repair install with .4349 always failed at first boot - could it be because it tried to create a 200MB EFI partition and there's no room? After the error PC wouldn't boot, just stayed on the Windows logo with no spinning circle.

BSOD SETUP_FAILURE during repair install

Attempting to do a Repair install using the latest ISO from MS (26100. 4349) Two attempts have failed at the same point. The initial copying process completes but the crash occurs after the first restart I get the Windows logo and spinning circle for a minute or so (maybe longer) then the error...

www.elevenforum.com

Winuser · Sep 14, 2025

Reading this thread has made me curious. All of my desktop computers are PowerSpec computers. PowerSpec computers are on line with being a BIY computer except that they chose the hardware. The EFI partitions on them are all 100MB. Will this always be big enough space? If not I'm I right in thinking that if more space is needed when Windows is doing an update that the update would make the change automatically. Am I correct or would the update fail forcing me to manually make the change. By doing a internet search I have seen post suggesting to delete the hidden partition between the EFI and Windows partition. That to me sounds like it would create a disaster waiting to happen.

garlin · Sep 14, 2025

There isn't an universal answer for everyone, other than proactively assigning more EFI space. Windows itself can get by with 100 MB, but it's really what other non-MS vendors or system tools consume in the EFI partition that get you into trouble.

Windows stores copies of the boot manager, fonts related to boot manager, and memtest. That doesn't really require too much room. The problem comes on the uncommon occasion Windows has to replace these files (normally for security vulnerabilities). The worse case is EFI temporarily gets two copies of every Windows files) before getting cleaned up.

Vendors at the scale of Dell can afford to hire devs to write proprietary system or BIOS management tools. They will tuck their code inside EFI. You may never buy a system from them, or own a management or security product that writes code to the EFI.

BitLocker recommends at least 250 MB for support.

If you know your system well, then it can be an informed choice. For most normal users, losing 100-160 MB of extra space just to avoid any future headaches is probably a good move.

gunrunnerjohn · Sep 14, 2025

I guess if you're really paranoid you can use one of the many disk management applications to move your Windows partition over a tad and expand the EFI partition to the desired size. Since my systems got fresh Windows installations direct from Microsoft downloads, they have 100MB EFI partitions.

Winuser · Sep 15, 2025

I'm not planning on messing with the EFI partition size. I'm just wonder if one had to increase the EFI partition size for what ever reason would it be possible.

gunrunnerjohn · Sep 15, 2025

Winuser said:
I'm not planning on messing with the EFI partition size. I'm just wonder if one had to increase the EFI partition size for what ever reason would it be possible.

Sure it is, I just fired up MiniTool Partition Manager First I shrunk my Windows partition by 102MB and moved it to the right.

Then I extended the EFI partition from 100 to 202MB, note the EFI partition is now 202MB in size.

I didn't apply the changes as I don't want to change anything unless it's necessary, but it's certainly easily possible if needed.

andrew129260 · Sep 15, 2025

garlin said:
If you know your system well, then it can be an informed choice. For most normal users, losing 100-160 MB of extra space just to avoid any future headaches is probably a good move.

garlin said:
There isn't an universal answer for everyone, other than proactively assigning more EFI space. Windows itself can get by with 100 MB, but it's really what other non-MS vendors or system tools consume in the EFI partition that get you into trouble.

I made my custom images for work and personal with 300 MB. Wanted to avoid any headaches down the road.

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

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