Converting MBR to GPT for EFI boot?

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  1. Posts : 2
    Windows 10
       #1

    Converting MBR to GPT for EFI boot?


    I've just recently re-installed Windows on my laptop. I had the hard drive set to a GPT format disk since my system supports and previously used UEFI boot, but this install wouldn't allow it so I just went to MBR again..

    Is there a way to convert the currently MBR type disk to a GPT format (without losing the current Windows installation) so I can resume using the UEFI format boot? I'd like to later dual boot Linux and I'd pref having a UEFI load over the MBR when that time comes.



    Thanks.
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  2. Posts : 141
    windows 10
       #2

    You can Convert MBR to GPT using Diskpart
    This method you have to backup all your data and delete all partitions and volumes. Then use the DISKPART command
    Open command prompt and type in DISKPART and press Enter
    Then type in list disk (Note down the number of disk you want to convert to GPT)
    Then type in select disk number of disk
    Finally type in convert gpt.
    EaseUS partition master can do it wihout data loss too, you can try it.
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  3. Posts : 5,169
    64bit Win 10 Pro ver 21H2
       #3

    You can do this and keep all your data. I recently did this on my Windows 10 installation and I followed the procedure described in the youtube clip below. It all went fairly smoothly apart from step 4 where I had to do a deep search in testdisk to identify the partitions that needed to be written.

    I would recommend that you study the video a few times to become familiar with each step and also have a hard copy of the steps printed out or at least a second computer nearby that you can refer to if you need to check on what to do next.

    https://youtu.be/Qk6_K9hVu_k

    I notice that the author has also written a simpler procedure that you can follow here:

    https://www.youtube.com/watch?v=g1eXD30Fox4

    Cheers,
    Phil
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  4. Posts : 2
    Windows 10
    Thread Starter
       #4

    philc43 said:
    You can do this and keep all your data. I recently did this on my Windows 10 installation and I followed the procedure described in the youtube clip below. It all went fairly smoothly apart from step 4 where I had to do a deep search in testdisk to identify the partitions that needed to be written.

    I would recommend that you study the video a few times to become familiar with each step and also have a hard copy of the steps printed out or at least a second computer nearby that you can refer to if you need to check on what to do next.

    https://youtu.be/Qk6_K9hVu_k

    I notice that the author has also written a simpler procedure that you can follow here:

    https://www.youtube.com/watch?v=g1eXD30Fox4

    Cheers,
    Phil
    Thanks a lot Phil, this is exactly what I needed!
      My Computer


  5. Posts : 2,799
    Linux Mint 20.1 Win10Prox64
       #5

    How to Convert from MBR to GPT:

    1. Download and install Macrium Reflect Free and create a backup image of your current MBR Windows 10 to an external HD. (You should anyway before modifying any Windows partitions in case something goes wrong)
    2. Create a bootable Macrium Rescue disk on a USB/DVD (from Macrium application, click on the first icon on the top left)
    3. Next, wipe out the disk and install a fresh copy of Windows 10 using GPT partition scheme. The installation should create all the needed partitions and C drive. No need to run updates because you're going to overwrite the C drive with the C drive from the backup.
    4. Next you'd want to ovewrite the C partition from fresh install with the C partition from the backup image.
      Boot up from the Rescue Image and follow the steps in the video as shown below and you're done.

    Last edited by topgundcp; 02 Jan 2017 at 21:56.
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  6. Posts : 5,169
    64bit Win 10 Pro ver 21H2
       #6

    Topgundcp, I agree your process using Macrium Reflect will be easier and more straightforward but the OP had difficulty doing a fresh install and achieving a GPT partition scheme. At your Step 3 he could run into the same problem again and be no better off.
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  7. Posts : 2,799
    Linux Mint 20.1 Win10Prox64
       #7

    philc43 said:
    Topgundcp, I agree your process using Macrium Reflect will be easier and more straightforward but the OP had difficulty doing a fresh install and achieving a GPT partition scheme. At your Step 3 he could run into the same problem again and be no better off.
    If the OP cannot install Windows using GPT partition scheme then there's something wrong with his settings in the BIOS and/or the selection of which option to boot from. I also thought of his idea is he wants to convert it into GPT without losing any installed applications/data.

    Anyway, he needs to fix the problem that he cannot install using GPT first.
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  8. Posts : 3,257
    Windows 10 Pro
       #8

    There's more to getting an EFI boot than just converting it to GPT. You also need to repartition to add the EFI boot partition, and another partition which I can't remember the name of that holds system files.

    Try this video Convert Windows 7/8/10 Installation from Legacy to UEFI Without Data Loss (Simpler Method) - YouTube
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  9. Posts : 2,799
    Linux Mint 20.1 Win10Prox64
       #9

    @Mystere
    The link you posted was already posted in #4. What I suggested above is simply overwrite the C partition with Macrium and it automatically convert this partition to GPT and Windows will boot up with no problem. Been there, done that.

    In addition, the method I used will properly align all partitions as if you do a fresh install without using diskpart to create/convert/format all the needed partitions. Windows is smart enough to re-assign the GUID to point at the C-Drive.
      My Computer


  10. Posts : 3,257
    Windows 10 Pro
       #10

    topgundcp said:
    @Mystere
    The link you posted was already posted in #4. What I suggested above is simply overwrite the C partition with Macrium and it automatically convert this partition to GPT and Windows will boot up with no problem. Been there, done that.

    In addition, the method I used will properly align all partitions as if you do a fresh install without using diskpart to create/convert/format all the needed partitions. Windows is smart enough to re-assign the GUID to point at the C-Drive.
    Sorry, I missed the first link. But no, converting it to GPT will not make it automatically an EFI boot. There is more to it, yes it may boot up, but won't be EFI.
      My Computer


 

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