Solved Installing Windows 11 IoT Enterprise LTSC on old hardware

Hi.
I recently decided to try to install Windows 11 on my old computer (LGA775) for academic purposes only. But I encountered several issues while trying to do a clean installation. So I prepared a USB bootable flash drive with Windows 11 IoT Enterprise LTSC using Rufus, but when I tried to boot from the flash drive, the installation was stuck on the screen with the

• Windows 11 logo
• text "Press any key to boot from USB"

in both cases, no matter what I did or pressed, I couldn't proceed.
After that, I tried to upgrade from the Windows 10 IoT Enterprise LTSC that had already been installed on my computer to Windows 11 by mounting .iso file and running installer. To my surprise, the installation process itself was successful (at least it looked like it), but after rebooting, instead of Windows 11, I got the error "A disk read error occurred". This forced me to do a clean install back to Windows 10.
I should also mention that I am trying to install Windows on my NVMe SSD Samsung 950 Pro, which is connected to the PCIe x16 slot via an adapter.
As I understand it, the LTSC edition of Windows 11 is based on the 24H2 update that requires the SSE 4.2 instruction set, which my processor does not have. But I read that the IoT Enterprise version should not have hardware requirements, or do the SSE 4.2 requirement still remain? Because the installation (upgrade) process from Windows 10 to 11 went without any obvious errors at the stage of checking the compatibility of my hardware.
Therefore, I would like to ask, is there no way to install Windows 11 24H2 (regardless of which edition) on my hardware due to the lack of SSE 4.2, or could the problem be something else?
Thanks.

adziri said:

CPU: Intel Core 2 Extreme QX9770

Windows Build/Version Windows 10 IoT Enterprise LTSC 24H2/26100.1742

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This is your problem, the Core 2 lacks the SSE4.2 instruction set without which any edition of 24H2 cannot even boot.

This requirement is impossible to bypass, the kernel code actually uses those missing instructions. 23H2 is the last version of Windows 11 that this PC can run.

Bree said:

I'm doing a clean install now on an old laptop without SSE4.2....

First issue was that it couldn't even boot from the standard 24H2 install USB made by the MCT. It gets as far as the Windows logo, then reboots before it even starts the spinning 'loading up' circle.

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Windows 11 24H2 has un-bypassable hardware requirements... - post #282

Bree said:

This is your problem, the Core 2 lacks the SSE4.2 instruction set without which 24H2 cannot even boot.

This requirement is impossible to bypass, the kernel code actually uses those missing instructions. 23H2 is the last version of Windows 11 that this PC can run.

Windows 11 24H2 has un-bypassable hardware requirements... - post #282

Click to expand...

Got it, thanks.
I was just confused that installing Windows 11 by mounting the .iso file and running the installer from Windows 10 on my PC went without any obvious errors, only after restarting I got "A disk read error occurred". I thought maybe the problem was something else, like my SSD.

And am I correct in understanding that the LTSC edition of Windows 11 does not have version 23H2?

adziri said:

And am I correct in understanding that the LTSC edition of Windows 11 does not have version 23H2?

Click to expand...

That's correct. There has only been one release of Windows 11 LTSC, and it's build 26100 (24H2).

adziri said:

am I correct in understanding that the LTSC edition of Windows 11 does not have version 23H2?

Click to expand...

Correct. The previous LTSC version was Windows 10 Enterprise LTSC 2021 Windows 10, Version 21H2

Then I have one more question. If I install Windows 11 version 23H2 (not LTSC), is it possible to force Windows not to install any updates? I wouldn't want to accidentally update to 24H2 after everything, which may break my system. Or would Windows itself not install this update because it is not compatible with my hardware?

adziri said:

Then I have one more question. If I install Windows 11 version 23H2 (not LTSC), is it possible to force Windows not to install any updates? I wouldn't want to accidentally update to 24H2 after everything, which may break my system. Or would Windows itself not install this update because it is not compatible with my hardware?

Click to expand...

The second one. Windows Update will not offer a feature update to an unsupported device. It will however get all the updates for your installed version (23H2) just like any supported device. Note that 23H2 reaches end of support in November 2025, there will be no further cumulative updates after that, though it should continue to get Defender AV definitions.

Bree said:

The second one. Windows Update will not offer a feature update to an unsupported device. It will however get all the updates for your installed version (23H2) just like any supported device. Note that 23H2 reaches end of support in November 2025, there will be no further cumulative updates after that, though it should continue to get Defender AV definitions.

Click to expand...

Thanks, I understand that. But for me it's not a big deal since I'm going to install this on my "retro PC" and wanted to see how it would feel with Windows 11. Eventually I'll probably go back to Windows 10 or even 7 for retro gaming

Here's another option :

adziri said:

Thanks, I understand that. But for me it's not a big deal since I'm going to install this on my "retro PC" and wanted to see how it would feel with Windows 11. Eventually I'll probably go back to Windows 10 or even 7 for retro gaming

Click to expand...

Understood.

It should run as well as Windows 10 does, maybe a little better (memory management is improved in W11).

If your W10 is activated with a digital licence, then that will also activate the same edition of W11 (Home or Pro). MS made no changes to the licensing for 11, all keys and digital licences are valid for both 10 and 11.

BTW, welcome to Eleven Forum.

So, it's been about a week since I installed Windows 11 IoT Enterprise 23H2 on my old PC, and I’d like to share my impressions.

1. I haven’t noticed a big difference between Windows 10 and Windows 11 in terms of resource usage or overall system performance.
2. Windows 11 behaves quite stably (with a few exceptions, which I’ll mention below). There have been no sudden crashes or blue screens. I also tried running several benchmarks like 3DMark to see how the system performs under load—no issues were detected.
3. But there are some problems. The most annoying one is that some (though not all) programs and/or installers refuse to run and crash. I can recall at least three programs: OCCT, Cinebench, and the Corsair iCUE installer. When trying to launch these programs/installers, nothing happens—the process briefly appears and immediately disappears. In the Event Viewer, there are always at least two errors per program: one with 'Exception code: 0xc000001d', and another stating 'Windows cannot access the file for one of the following reasons: there is a problem with the network connection, the disk that the file is stored on, or the storage drivers installed on this computer; or the disk is missing' (I’ll include more detailed reports on these errors below). In an attempt to figure out the cause, I tried a bunch of methods, including:
   • Dism /Online /Cleanup-Image /ScanHealth
   • Dism /Online /Cleanup-Image /CheckHealth
   • Dism /Online /Cleanup-Image /RestoreHealth
   • sfc /scannow
   • chkdsk /f /r
   • I also installed all available updates.
   But none of that helped. So I went further and decided to dig deeper to understand what was causing it. I downloaded WinDbg and started debugging. It turned out that the issue was due to an attempt to use the SSE 4.2 instruction popcnt, which my processor does not support.
   I’m not sure whether this is a Windows issue, a problem with the individual programs, or something that can be fixed.

Apparently Windows 11 is not the best choice for such hardware