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Switch Windows to UEFI mode without reinstalling Windows.

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PikaaxYT Posted messages 8 Status Member -  
fabul Posted messages 42136 Registration date   Status Moderator Last intervention   -

Hello, I'm considering upgrading to Windows 11 as the end of updates for Windows 10 is approaching, but the problem is that when I installed Windows, I did it in MBR and now I can't switch to Windows 11. When I searched on Google for how to switch to UEFI, I was told that Windows wouldn't boot anymore and that I would have to reinstall Windows. Is it possible to switch to UEFI without reinstalling Windows?

Thank you in advance,

1 answer

  1.
    fabul Posted messages 42136 Registration date   Status Moderator Last intervention   6 062
     

    Hello,

    A very short, but easy-to-follow summary

    > Settings
    > Updates & Security
    > Recovery
    > Restart

    In recovery mode
    > Troubleshoot
    > Command Prompt

    mbr2gpt /validate
    mbr2gpt /convert

    After that, you will need to switch your BIOS to UEFI (Non CSM) to be able to boot

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    1. epango Posted messages 37195 Registration date   Status Member Last intervention   4 270
       

      Are you sure that Mr. or Mrs. Everyone understands what you are advocating?

      0
      1. fabul Posted messages 42136 Registration date   Status Moderator Last intervention   6 062 > epango Posted messages 37195 Registration date   Status Member Last intervention  
         

        You need to click everywhere there is a >

        > Settings
        > Updates and Security
        > Recovery
        > Restart
        > Troubleshoot
        > Command Prompt

        Enter command #1 mbr2gpt /validate
        Then command #2 mbr2gpt /convert

        Switch the BIOS to Non CSM or UEFI mode

        These are the notes I took when I did it, and it worked.

        How can I be clearer and more concise at the same time?

        Have a good day.

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      2. SATS_fr Posted messages 4849 Registration date   Status Member Last intervention   785 > fabul Posted messages 42136 Registration date   Status Moderator Last intervention  
         

        Hello.

        From what I've seen, your manipulation works if there's only one disk; otherwise, you need to select the disk to convert with diskpart ( https://www.malekal.com/comment-passer-un-pc-de-legacy-herite-en-uefi-pour-installer-windows-11/ ).

        Otherwise, check if the free version of Aomei Partition Assistant allows the conversion from MBR to GPT. (I only have GPT partitions, so I can't test).

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      3. fabul Posted messages 42136 Registration date   Status Moderator Last intervention   6 062 > SATS_fr Posted messages 4849 Registration date   Status Member Last intervention  
         

        I have 2 NVMe SSDs and 4 HDDs and it worked right away for me, but this is not to criticize your info, indeed, some may experience issues, it can help.

        And indeed, sometimes even Windows' WinPE can't find C;\...

        @+

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