Windows 11 25H2 and the EFI Partition

I have a small MeLE mini computer that is having an issue with 25H2. I used the Enablement Package to upgrade it from 24H2 to 25H2. No problems. Then an update for .NET came through which apparently was a 25H2 version update replacing the 24H2 version I had installed a few days ago. This update hung. In messing around without much of a resolution and thinking something may be amiss now with the computer, I decided to do an in-place repair using the 25H2 MCT. That went pretty well, but when it got to the point where it checked to see if there was enough disk space available for the install, I received this wonderfully worded message "We can't tell if your PC has enough space to continue installing Windows 11. Try restarting Setup". Well I have over 1.5 TB free on my hard drive, so I knew this was a message that did not make much sense. After wandering around the web I found there were a number of similar complaints. The resolution was to increase the size of the EFI partition. This PC came with a 100mb EFI partition which was fine for all previous versions of Windows 11, but not for 25H2. It would have been nice for Microsoft to say that the size of the EFI partition could be an issue with this update instead of the message they give you. So be aware that this could be an issue.

JohnD

I usually create 300mb esp it is the default offered by diskgenius

There are Windows upgrade failures for insufficient free space in each of the four default partitions.

Unfortunately upgrade failures can report general error messages.

To get a better understanding of upgrade failures the upgrade failure log files can be scanned and read.










Please run these scripts > post share links




1) V2 log collector:





2) Tuneup plus:







3) upgrade_failure_info:

johnpd said:

The resolution was to increase the size of the EFI partition. This PC came with a 100mb EFI partition which was fine for all previous versions of Windows 11, but not for 25H2. It would have been nice for Microsoft to say that the size of the EFI partition could be an issue with this update instead of the message they give you. So be aware that this could be an issue.

Click to expand...

One of the reasons for increasing the EFI partition size (typically to around 200-400 MB), is that several OEM's will stage firmware images on the EFI while updating the BIOS. The bad part is they don't really bother cleaning up the EFI after they're done. This causes a space problem when MS has to replace the boot files due to a known security problem.

In the old days, EFI and Recovery were mostly static and didn't really that much space. But increased attention to system security has forced MS to more constantly update EFI and WinRE to fix security holes.

johnpd said:

"We can't tell if your PC has enough space to continue installing Windows 11. Try restarting Setup". Well I have over 1.5 TB free on my hard drive, so I knew this was a message that did not make much sense. After wandering around the web I found there were a number of similar complaints. The resolution was to increase the size of the EFI partition. This PC came with a 100mb EFI partition which was fine for all previous versions of Windows 11, but not for 25H2. It would have been nice for Microsoft to say that the size of the EFI partition could be an issue with this update instead of the message they give you. So be aware that this could be an issue.

JohnD

Click to expand...

The EFI partition size like the primary partition (C:) is fixed.

Over time computer users download and install files.

Unknowingly some may be installed in the EFI partition.

During upgrades the same more or less free space may be required.

The partition size may have insufficient free space for new upgrades.

It's a dynamic process with a fixed partition size.




The size and contents of the EFI partition can be viewed.

Files can be temporarily or permanently deleted from the EFI partition for the upgrade.

Alternatively some partitions may be widened or relocated and enlarged.