Cannot use Rufus to install Windows 11

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I am unable to use Rufus to install Windows 11 on my unsupported CPU (Intel Core TM Quad CPU Q9400).

The error message says:

The installation failed in the SAFE_OS phase with an error during BOOT operation

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Barnec15E wrote:

I am unable to use Rufus to install Windows 11 on my unsupported CPU (Intel Core TM Quad CPU Q9400).

There is an updated version of Rufus 4.6. If you are seeing THIS message, it means your CPU will not run on Win11 24H2 period. (But you could try an older version of Win11 like 23H2.)

https://github.com/pbatard/rufus/wiki/FAQ

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@Barnec15E –

After finding the specs for your processor on Intel’s site, there is no spec for Instruction Set Extensions, which is where one would find if your processor supports SSE 4.2. Since there is no listing for Instruction Set Extensions, there are none for it. Therefore, it doesn’t support SSE 4.2 and is not able to run windows 11 24H2.

Here’s the link to the full specs from Intel for your processor:

https://ark.intel.com/content/www/us/en/ark/products/35365/intel-core-2-quad-processor-q9400-6m-cache-2-66-ghz-1333-mhz-fsb.html

If it supported any type of Instruction Set Extensions, that fact would be listed right under the listing for “Instruction Set”.

So, as @PL1 suggests, you might want to settle in and get comfy running 23H2 until it’s no longer supported by Microsoft. Sorry. 

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PL1

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Hey Y’all,

The Free CPU-Z program will tell you all about your CPU including the instruction set extensions it supports.

May the Forces of good computing be with you!

RG

PowerShell & VBA Rule!
Computer Specs

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Alex5723, PL1, Bob99

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Windows 11 24H2 isn’t supported on any Core 2 CPU and there’s no workaround.

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There may be with UnattendedWinstall script

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PL1

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Windows 11 24H2 requires a CPU that supports SSE 4.2 and that cannot be bypassed!

Windows 11 24H2 won’t boot if the CPU doesn’t support SSE 4.2.

Since the OP’s CPU only supports up to SSE 4.1 (Intel Core 2 Quad Q9400 – see the Features section), the Rufus “bypass H/W requirements” process can only be used to install Windows 11 23H2, which reaches end of support in October 2025 just like Windows 10 22H2

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steeviebops

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Thanks all for the details. I will try 23H2 instead.

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