Creator's Update- Disk Layout for UEFI firmware isn't supported error

Hi,
Not that you have legacy bios although you show little to no system spec's of what mother board/ cpu/.... you have installed other than "custom build" so it's not much to go on :)

But on another note it seems to me the so called "creators build" is the first step to discontinue support for legacy bio's meaning older hardware will not be supported anymore for this or other future builds of win-10 seeing legacy bios does not support uefi so anyone that does have legacy bios is out of luck and stuck on the build they have now.
Good to know though the game seems to be changing uefi was said to not be mandatory but it seems MS has changed their mind again

ThrashZone said:

But on another note it seems to me the so called "creators build" is the first step to discontinue support for legacy bio's meaning older hardware will not be supported anymore for this or other future builds of win-10 seeing legacy bios does not support uefi so anyone that does have legacy bios is out of luck and stuck on the build they have now.

Absolute nonsense. The OP has a completely non-standard disk format, that is all the upgrade is complaining about. His disk format is not standard for either legacy BIOS or UEFI. He probably has CSM mode enabled in his UEFI firmware which is the only way his current disk format will boot. The upgrade is seeing his computer has UEFI firmware and it is looking for an EFI system partition to update - and there isn't one. If the computer did have a true legacy BIOS, there would be no problem, even though the disk layout is still pretty non-standard for legacy BIOS.

sygnus21 said:

Looking at your supplied Disk Management panel I can see your drive isn't formatted for UEFI. If it was it would look something like mine (or anyone else installed under UEFI)...

My drives do have those partitions and the drives are GPT. However I too get the same error message

@AndreyT, I would try moving the pagefile from drive D: to drive C:. Also, instead of using the upgrade assistant, I would download the ISO file using the Media Creation Tool, mount the ISO file, and run setup.exe from the mounted ISO file.

My 3-month old Win10 computer shows 4 partitions on the 1TB drive with only C: and D: being lettered, default install of Win10. I believe that's the proper way it should be done.
Attachment 129777

Took some figuring out from this thread and several others, but I finally solved the identical issue on my end and I'm hoping this serves as a guide for others:

My error was identical to the OP when updating to Windows 10 version 1703. Following the below link, I was able to find the error log from C:\$Windows.~BT\Sources\Panther\setupact.log.
[FIX] Windows Cant Be Installed Because This PC Has An Unsupported Disk Layout For UEFI Firmware

Went through recommended troubleshooting, recreating MSR with DISKPART - no dice.

Looking at the log more carefully revealed something strange, specifically the following line:
CONX ConX::Compatibility::CSystemAbstraction::GetSystemVolumeNtPath: Detected system partition NT path: [\Device\HarddiskVolume3]

Returned to Diskpart > list volume, it appears that C was actually Volume 5, not Volume 3 as detected.

My volume 3 actually contains my secondary boot option of Windows 7 which is not UEFI. This seems to be the root of the problem.

A quick trip to the bios allowed me to disable that drive's SATA port.

Rebooted Windows 10 without the drive, install performs as intended. It appears this specific update is not correctly identifying the drive. If you take away these other drives as options for failure, you'll force it to update on the correct drive alone.

TLDR: If you're getting this error with more than one drive, simply disable all hard drives but C where possible. This should solve your issue if you're sure you're setup for UEFI on your active GPT disk with a proper MSR.