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Modify the Windows 11 IoT LTSC 24H2 ISO image language

IdeDx 40 Reputation points
2025-06-07T22:21:04.3533333+00:00

Good morning, I would like to ask for help making some changes to the Win 11 IoT LTSC 24H2 ISO image downloaded from the official Microsoft website. It is only available in English US. I need to change it to Spanish Mexico. I managed to install the es-MX language pack, but I had two problems and I would like to know if it is possible to fix them, please:

1.- When I start the ISO already modified with the es-MX language, the first option is US English. I have to manually select es-MX to change it.

Is there a way to set the es-MX language as the default so that the installation always starts with that language and leaves US English as the secondary language?

1.pngIdetX · Jun 2, 2025 at 3:53 PM

2.- When I enter Repair my computer in the Windows installation of this ISO, it takes me to the Recovery Menu, but even though I select the Spanish Mexican language, it still appears in English US. Is there a way to set the recovery menu language to es-MX? Or can it be configured so that when I select the es-MX language, the recovery menu changes to es-MX, and when I select English/US, it also changes to English US?

2.pngIdetX · Jun 2, 2025 at 3:53 PM

I appreciate the help. Another option would be to install Windows 11 IoT LTSC 24H2 in English, and once installed, download and install the Mexican Spanish language pack. However, in my last post and other posts, it was reported that the Windows 11 24H2 version is having issues when changing languages. I managed to more or less solve this problem as I mentioned in my post, but it doesn't always work on all computers, and I want to try changing the language of the Windows 11 IoT LTSC 24H2 ISO downloaded from the official Microsoft website.

Thanks for the help and attention. 👍

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  1. Anonymous
    2025-06-12T03:22:31.35+00:00

    Hi IdeDx,

    To modify the Windows 11 IoT LTSC 24H2 ISO to default to Spanish Mexico (es-MX) and fix the recovery environment language, follow these structured steps:

    Step 1: Prepare Tools and Files

    1. Download Required Tools:
    2. Get Language Files:
      • Download the official es-MX language packs for 24H2:
        • WinPE (Setup Environment): Microsoft-Windows-WinPE-LanguagePack-Package_es-mx.cab
        • Full OS: Microsoft-Windows-Client-Language-Pack_x64_es-mx.cab
      • Source: Extract from a multi-language ISO or download via Microsoft Update Catalog (search "Windows 11 24H2 amd64 language pack").

    Step 2: Modify Setup Default Language (boot.wim)

    Goal: Force setup to start in Spanish Mexico by default.

    1. Extract ISO → Open \sources\boot.wim in NTLite.
    2. Load Index 1 (Windows Setup GUI):
      • Add WinPE es-MX CAB under Packages → Apply.
      • Set default language: 
        
     dism /image:C:\Mount /Set-SKUIntlDefaults:es-MX
    3. Load Index 2 (WinPE Recovery):
      • Repeat language pack integration.
    4. Rebuild boot.wim → Replace in ISO.

    Step 3: Set OS Default Language (install.wim)

    Goal: Ensure installed OS uses es-MX.

    1. Open \sources\install.wim in NTLite.
    2. Add Full Language Pack:
      • Integrate Client-Language-Pack es-MX CAB.
    3. Set Defaults: 
      
   # Mount image

   dism /Mount-Image /ImageFile:install.wim /Index:1 /MountDir:C:\Mount

   # Set language defaults

   dism /Image:C:\Mount /Set-SKUIntlDefaults:es-MX

   dism /Image:C:\Mount /Set-AllIntl:es-MX

   dism /Image:C:\Mount /Gen-LangINI /distribution:C:\ISO\Sources

   # Unmount

   dism /Unmount-Image /MountDir:C:\Mount /Commit
    4. Edit \sources\lang.ini: 
      
   [Available UI Languages]

   es-MX = 10  ; Ensure higher priority than en-US

   en-US = 3

   [Default UI Language]

   = es-MX

    Step 4: Fix Recovery Environment (winre.wim)

    Goal: Translate WinRE to Spanish.

    1. Extract WinRE from mounted install.wim:
      • Path: Windows\System32\Recovery\winre.wim
    2. Modify with DISM++:
      • Mount winre.wim → Add WinPE es-MX CAB.
      • Set default language: 
        
     [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MUI\UILanguages]

     "es-MX"=hex(7):00
    3. Repack & Replace:
      • Save modified winre.wim back to install.wim and ISO.

    Step 5: Rebuild ISO

    1. Update Files:
      • Replace modified boot.wim, install.wim, and lang.ini in \sources.
    2. Repackage ISO with UltraISO:
      • Save as UDF format, preserve boot sectors.

    Verification Checklist

    | Component | Action | Tool Used |

    |---------------------|--------------------------------------------|------------------|

    | Setup (boot.wim) | Set es-MX as first language | NTLite + DISM |

    | OS (install.wim) | Default user/profile to es-MX | DISM |

    | Recovery (winre.wim)| Full Spanish UI | DISM++ |

    | ISO Structure | Bootable UDF with updated lang.ini | UltraISO |

    Critical Notes

    1. Language Pack Compatibility:
      • Ensure CABs match 24H2 build 26100.1 (exact version required).
    2. WinRE Dependencies:
      • Add WinPE fonts (winpe-font-*.cab) to prevent missing glyphs in recovery.
    3. Testing:
      • Validate in Hyper-V before deployment: 
        
     New-VM -Name "LTSC-Test" -MemoryStartupBytes 4GB -NewVHDPath "C:\VHDs\LTSC.vhdx" -NewVHDSizeBytes 40GB

    Alternative: Post-Installation Fix (If ISO Mod Fails)

    1. Install in English → Add es-MX via: 
      
   # Download language pack

   Add-AppxPackage -Path "https://software-static.download.prss.microsoft.com/.../es-mx.lp.cab"

   # Set defaults

   Set-WinSystemLocale -SystemLocale es-MX

   Set-WinUILanguageOverride -Language es-MX
    2. Force WinRE Regeneration: 
      
   reagentc /disable

   reagentc /enable

    By following these steps, the ISO will default to Spanish Mexico during setup and recovery. For persistent language issues in 24H2, consider deploying the latest cumulative update (KB5039302+) which resolves locale bugs.

    Please feel free to let me know if you still have any questions.

    Best regards,

    BblytheX

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  1. IdeDx 40 Reputation points
    2025-08-12T21:51:57.0233333+00:00

    To definitively solve the mixed language problem mentioned in my previous comment, despite having installed the es-MX language pack in the ISO image and selecting that language:

    Once again, I would like to thank BblytheX for giving me an idea and a reason to try to solve it. they have already released an update that fixes this mixed language problem, but possibly the Windows 11 IoT 24H2 LTSC ISO downloaded from the official Microsoft website does not yet have that update. If I remember correctly, a few weeks ago I downloaded it again but saw that it was the same GB and name, so it is still the same ISO without the patch to fix this problem (if I am not mistaken).

    I previously installed Windows 11 IoT LTSC 24H2 with this mixed language bug, as I explained in my previous comment. I searched for updates from Windows Update even with the buttons and other elements invisible. I had to wait a few minutes for the updates to install without being able to see the progress. I had to wait until it told me to restart the PC from the Shut Down button in the Start menu. Once restarted, everything returned to normal and the update problem was fixed.

    That bothered me, because every time I installed Win 11 IoT LTSC 24H2 with the es-MX language, I had to search for updates from Windows Update. I couldn't do anything else because it gave me an error when opening other Windows programs due to the mixed language. So, thanks to BblytheX's suggestion to implement an update to fix this problem, I decided to try it and managed to solve it:

    SOLUTION:

    I downloaded these two updates from the Windows update catalog:

    User's image

    Using NTLite to find out which ones my ISO needed. I downloaded these two because one depends on the other. Then I followed an XDA article to implement updates in an ISO image using DISM commands. I implemented them and tested the ISO on a virtual machine, and now I had no problems. The language remained 100% es-MX, and I also changed the language of the system recovery menu. I extracted the Winre.wim file from the path \windows\system32\ recovery from the install.wim file of the normal Windows 11 ISO in es-MX language and replaced it with the Winre.wim file in the install.wim file in the path \windows\system32\ recovery path of my Win 11 IoT LTSC 24H2 ISO image. I also used the same DISM command from the XDA guide to mount the Win 11 IoT LTSC install.wim file and make the Winre.wim change there. Finally, I used NTLite to create the ISO image.

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  2. IdeDx 40 Reputation points
    2025-08-12T20:33:14.6966667+00:00

    I also encountered problems after installing Windows 11 IoT LTSC 24H2 even though I had installed the es-MX language. Some things still appeared in English and Spanish, as if the English language was still active even though I had selected only the es-MX language to install in Windows. Even when searching for updates in Windows Update, it caused a bug where it hid messages and the Search for updates button itself.

    User's image

    I already reported this in my post at the end of March this year. In fact, I read news reports about this problem in version 24H2:

    User's image

  3. IdeDx 40 Reputation points
    2025-08-12T20:18:22.2966667+00:00

    Better late than never.

    Thank you very much for your help, BblytheX. Thanks to your guidance, I got an idea of how to modify the ISO to leave it in Spanish-MX. In the end, I found it difficult to try to extract the languages and add them to the Windows 11 IoT LTSC 24H2 ISO to have both languages installed. What I did, and found easier, was to copy the boot. wim file from the normal Windows 11 24H2 ISO (not IoT LTSC) and pasted it into the Windows 11 IoT LTSC 24H2 folder. This changed the Windows installation to es-MX, as well as the recovery menu. If I ever need to use it in English, I have the original ISO.

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