Install Windows 11 on an unsupported computer

LuchaEnErrrores · 2026-06-05T06:28:51-0400

Hello.

I'm trying to install Windows 11 on an unsupported computer without formatting the system. In the past, I was able to perform this procedure several times using known methods to bypass the hardware requirements, but recently I'm encountering problems I didn't have before.

I tried installing Windows 11 in Spanish (Mexico), and after the installation process finished and I restarted the computer, I received a message similar to: "Windows Server installation failed."

I also tried using a Windows 11 ISO in Spanish (Spain). In this case, when I selected the options "Keep files, settings, and apps" or "Keep only personal files," the installer displayed the message: "Cannot determine if your computer has enough space to continue installing Windows Server. Try restarting your setup."

I've used methods like AllowUpgradesWithUnsupportedTPMOrCPU and the setup.exe or setupprep.exe /product server parameter, which previously worked on other computers, but in this case, they haven't worked.

Does anyone know if there have been any recent changes to the Windows 11 installer or if there's an alternative method for upgrading on unsupported computers? I know this type of installation isn't officially supported and may involve risks or limitations, but I promised the person I'd do everything I could to try and install Windows 11, and I'd like to exhaust all available options before giving up.

OAT · 2026-06-05T07:25:39-0400

Hello,
Welcome to the forum.
It would be very helpful for potential helpers that you provide:

-Information about the target system, Motherboard, CPU , RAM etc.
-The version and build of the Windows installation.
-The method of installation ISO,USB etc.

Thanks.

Celery · 2026-06-05T07:29:31-0400

"We can't tell if your PC has enough space to continue installing Windows 11. Try restarting Setup."

"We can't tell if your PC has enough space to continue installing Windows Server. Try restarting Setup."

We can't tell if your PC has enough space to continue installing Windows Server.webp

Bree · 2026-06-05T07:42:38-0400

LuchaEnErrrores said:
Does anyone know if there have been any recent changes to the Windows 11 installer or if there's an alternative method for upgrading on unsupported computers?

Welcome to Eleven Forum.

A couple of days ago I tested a clean install of 25H2 on an unsupported device. It worked, after a bit of fiddling....

Bree said:
My first attempt failed with "Installation failed" after the install and all the reboots. But it's not what you think, it's not rejecting the MBR disk as unsuitable.

With 24H2 MS reworked Setup.exe to give it a new modern look. This introduced an obscure bug which made the install fail if the target drive was a native boot .vhdx. Well, you can now add MBR disks to that list. ... My second attempt succeeded, simply by switching to the previous version of Setup, a fix I had already discovered for a .vhdx install.

An in-place upgrade should work with the steps in Option Three here:

Bypass Windows 11 System Requirements on Unsupported PC

This tutorial will show you how to bypass the Windows 11 CPU, RAM, Secure Boot, and TPM 2.0 system requirements allowing you to clean install or upgrade to Windows 11 on a unsupported PC that doesn't meet these requirements. Installing Windows 11 on a device that does not meet Windows 11...

www.elevenforum.com

LuchaEnErrrores · 2026-06-05T10:22:44-0400

Bree said:
Welcome to Eleven Forum.

A couple of days ago I tested a clean install of 25H2 on an unsupported device. It worked, after a bit of fiddling....

An in-place upgrade should work with the steps in Option Three here:

Bypass Windows 11 System Requirements on Unsupported PC

This tutorial will show you how to bypass the Windows 11 CPU, RAM, Secure Boot, and TPM 2.0 system requirements allowing you to clean install or upgrade to Windows 11 on a unsupported PC that doesn't meet these requirements. Installing Windows 11 on a device that does not meet Windows 11...

www.elevenforum.com

not working

Megahertz · 2026-06-05T10:37:10-0400

Please edit your profile with ALL your hardware specs. It will help us to help you

System Specs - Fill in at Ten Forums

How to Fill in your System Specs at Ten Forums

www.tenforums.com

Is your system a Legacy - MBR or UEFI-GPT?
Please download and run whynotwin11
Post the results here as an attachment

How to Upload and Post Screenshots and Files at Ten Forums

How to Upload and Post a Screenshot and File at Ten Forums Information This tutorial will show you how to upload and attach a screenshot,

www.tenforums.com

LuchaEnErrrores · 2026-06-05T10:37:33-0400

OAT said:
Hello,
Welcome to the forum.
It would be very helpful for potential helpers that you provide:

-Information about the target system, Motherboard, CPU , RAM etc.
-The version and build of the Windows installation.
-The method of installation ISO,USB etc.

Thanks.

Celery said:

"We can't tell if your PC has enough space to continue installing Windows 11. Try restarting Setup."

"We can't tell if your PC has enough space to continue installing Windows Server. Try restarting Setup."

View attachment 173465

Click to expand...

It's a laptop. It has 4GB of RAM, an Intel(R) Pentium(R) CPU B950 @ 2.10GHz, 2100MHz, and the processor is the same. Motherboard manufacturer: Positivo BGH.
Motherboard model: C500. It runs Windows 10 Home Single Language, version 10.0.19045. It has 123GB of available storage space—too much space—and a 256GB solid-state drive.

LuchaEnErrrores · 2026-06-05T10:41:08-0400

Megahertz said:
Please edit your profile with ALL your hardware specs. It will help us to help you

System Specs - Fill in at Ten Forums

How to Fill in your System Specs at Ten Forums

www.tenforums.com

Is your system a Legacy - MBR or UEFI-GPT?
Please download and run whynotwin11
Post the results here as an attachment

Friend, if this isn't related to the problem of not being able to install Windows 11 on an incompatible computer, delete your post and create your own post with your title instead of posting here. Posting here is pointless and makes no sense.

Megahertz · 2026-06-05T10:54:48-0400

LuchaEnErrrores said:
Friend, if this isn't related to the problem of not being able to install Windows 11 on an incompatible computer, delete your post and create your own post with your title instead of posting here. Posting here is pointless and makes no sense.

Of course it is related
Your computer isn't on the Microsoft list so it's not supported.
Normal installation requires UEFI - GPT
And answers like "not working" doesn't help much. You're the one in front of your computer so explain in details what you're seeing.

I have Win 11 on my unsupported computers. You're the one that can't install.

Megahertz · 2026-06-05T11:21:15-0400

Use Rufus

Bypass Windows 11 System Requirements on Unsupported PC

This tutorial will show you how to bypass the Windows 11 CPU, RAM, Secure Boot, and TPM 2.0 system requirements allowing you to clean install or upgrade to Windows 11 on a unsupported PC that doesn't meet these requirements. Installing Windows 11 on a device that does not meet Windows 11...

www.elevenforum.com

Celery · 2026-06-05T11:25:05-0400

LuchaEnErrrores said:
I also tried using a Windows 11 ISO in Spanish (Spain). In this case, when I selected the options "Keep files, settings, and apps" or "Keep only personal files," the installer displayed the message: "Cannot determine if your computer has enough space to continue installing Windows Server. Try restarting your setup."

Google Gemini:

The EFI System Partition (ESP) is the most likely culprit behind this specific error message when your C: drive clearly has plenty of free space (123 GB).

Why the EFI System Partition causes this error
The error message "We can't tell if your PC has enough space to continue installing Windows 11" is notoriously misleading. It triggers not because your main C: drive is full, but because the Windows installer is blocked from reading or writing to one of the critical hidden system partitions.

The EFI System Partition typically formats as FAT32 and is usually only 100 MB to 260 MB in size. During a Windows 10 to Windows 11 upgrade, the installer must write new bootloader files to this partition. This process will fail if the EFI partition is crowded out by:

Leftover boot files from previous operating systems or dual-boots.

Over-logged data or language packs.

OEM/BIOS update logs written to the partition.

If the installer detects that the EFI partition doesn't have enough free overhead space (usually requiring at least 15 MB to 50 MB depending on the specific setup architecture), it throws the generic "can't tell if your PC has enough space" error.

What about the Recovery Partition?
While the Recovery Partition (WinRE) can sometimes cause Windows Update failures (often throwing error codes like 0x80070643), it is less likely to cause this specific block during an ISO in-place upgrade. If the Recovery Partition is too small, the Windows 11 ISO installer is usually capable of automatically shrinking the C: drive to create a new, appropriately sized Recovery Partition. However, it cannot easily resize or modify a congested EFI partition on the fly.

gunrunnerjohn · 2026-06-05T11:25:10-0400

I installed Windows 11 Pro on an eleven year old HP desktop with no TPM and an unsupported processor. The install went seamlessly simply using Rufus to configure the image before the install.

LuchaEnErrrores · 2026-06-05T12:07:00-0400

gunrunnerjohn said:
I installed Windows 11 Pro on an eleven year old HP desktop with no TPM and an unsupported processor. The install went seamlessly simply using Rufus to configure the image before the install.

Megahertz said:
Use Rufus

Bypass Windows 11 System Requirements on Unsupported PC

This tutorial will show you how to bypass the Windows 11 CPU, RAM, Secure Boot, and TPM 2.0 system requirements allowing you to clean install or upgrade to Windows 11 on a unsupported PC that doesn't meet these requirements. Installing Windows 11 on a device that does not meet Windows 11...

www.elevenforum.com

Oh yes. I did use Rufus, but it didn't work.

LuchaEnErrrores · 2026-06-05T12:14:34-0400

Megahertz said:
Of course it is related
Your computer isn't on the Microsoft list so it's not supported.
Normal installation requires UEFI - GPT
And answers like "not working" doesn't help much. You're the one in front of your computer so explain in details what you're seeing.

I have Win 11 on my unsupported computers. You're the one that can't install.

I don't know what else to tell you. It's UEFI GPT. Can you spherify me? Sorry if it looks weird. I use Google Translate to translate from English.

gunrunnerjohn · 2026-06-05T13:08:42-0400

LuchaEnErrrores said:
Oh yes. I did use Rufus, but it didn't work.

Didn't work? What didn't work? You need to be specific as to what you are doing and what you are seeing.

LuchaEnErrrores · 2026-06-05T13:20:42-0400

gunrunnerjohn said:
Didn't work? What didn't work? You need to be specific as to what you are doing and what you are seeing.

I inserted an empty 16GB USB drive. I removed the 4GB RAM requirement, disabled Secure Boot, TPM 2.0, and the Microsoft account, and even enabled and disabled data collection (skip privacy questions) and BitLocker automatic device encryption. After reinstalling, Setup.exe or Setupprep.exe still says it's not compatible and requires TPM 2.0 and a compatible processor. Nothing changed.

garlin · 2026-06-05T13:33:01-0400

I presume you're trying a live upgrade, and not a clean install? Try running this reg file before you execute Setup.exe or Setupprep.exe.

LuchaEnErrrores · 2026-06-05T13:43:24-0400

garlin said:
I presume you're trying a live upgrade, and not a clean install? Try running this reg file before you execute Setup.exe or Setupprep.exe.

I think I just used that somewhere else, but it still doesn't work.

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