Problem creating EFI system partition  

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  1. Posts : 187
    Windows 10 Pro 64Bit

    Problem creating EFI system partition

    Hi, My Windows 10 pro 64 bit is running on legacy mode. I want to run in UEFI mode but I have 2 recovery partions on my main drive.
    When I executed mbr2gpt /allowFullOS /validate on the admin CMD I got the following:
    ESP partition size will be 104857600
    2022-12-02 19:40:07, Info MBR2GPT: Validating layout, disk sector size is: 512 bytes
    2022-12-02 19:40:07, Error ValidateLayout: Too many MBR partitions found, no room to create EFI system partition.
    2022-12-02 19:40:07, Error Disk layout validation failed for disk 2
    What is the best way to fix this problem... Thanks
      My Computer

  2. Posts : 7,468
    windows 10

    Can you post a screenshot from diskmanger showing all details it sounds as if you have to many partitions as that what the error is
      My Computer

  3. Posts : 38,776
    Win 10 Pro (22H2) (2nd PC is 22H2)

    Hi, for anyone to consider this - why not post a screenshot of your partitions using a 3rd party partition manager such as Minitool Partition Wizard (not Disk Management)?

    Have you reviewed this tutorial and comments following?
    Convert MBR Disk to GPT Disk in Windows 10

    And before attempting such a major change, please confirm you have created a full current 3rd party disk image so you can readily recover should it all fall apart.

    I would also recommend as a matter of routine precaution that you check your disk before attempting this change.
    (E.g. Hard Disk Sentinel)

      My Computers

  4. Posts : 187
    Windows 10 Pro 64Bit
    Thread Starter

    Problem creating EFI system partition-disk-manager.jpg

    I ran reagentc /info command on admin CMD.
    Got the following info:
    Microsoft Windows [Version 10.0.19044.2251]
    (c) Microsoft Corporation. All rights reserved.

    C:\WINDOWS\system32>reagentc /info
    Windows Recovery Environment (Windows RE) and system reset configuration

    Windows RE status: Enabled
    Windows RE location: \\?\GLOBALROOT\device\harddisk3\partition2\Recovery\WindowsRE
    Boot Configuration Data (BCD) identifier: 4d14f667-c547-11ec-ae92-fe019c398463
    Recovery image location:
    Recovery image index: 0
    Custom image location:
    Custom image index: 0

    REAGENTC.EXE: Operation Successful.

    Looks like the Recovery Partition windows is using is partion 2.
    Can one of the other two recovery partitions be deleted?
    If so which one would be safe to delete.
    Last edited by Raner; 03 Dec 2022 at 08:02.
      My Computer

  5. Posts : 38,776
    Win 10 Pro (22H2) (2nd PC is 22H2)

    Thank you for your reply.

    Your screenshot is with Disk Management, not with a 3rd party partition manager.

    You can delete the Recovery partition not in use.
    I posted this yesterday in another thread. This should help you.

    Recovery partition deletion - Ghacks

    If you were to search tenforums you would find other examples of dealing with this.
      My Computers

  6. Posts : 4,870
    Windows 11 Pro 64-bit

    In this video, i will show you how to create EFI partition from within Windows Recovery Environment.

      My Computer

  7. Posts : 20,211
    Win 10 Home ♦♦♦19045.2788 (x64) [22H2]


    You already have 4 primary partitions on that disk.
    The MBR2GPT command can't do the conversion, because it has to create another primary partition, which it can't do.

    As mentioned above, you need to delete one of those Recovery partitions.
    Then, MBR2GPT should work.
      My Computer

  8. Posts : 187
    Windows 10 Pro 64Bit
    Thread Starter

    Thank you all for taking time to help me out.
    According to what I'm seeing the following is the recovery partition windows is using:
    Windows RE location: \\?\GLOBALROOT\device\harddisk3\partition2\Recovery\WindowsRE
    So looks like the other two recovery partitions ( In my case Disk3 partition 3 and 4 ) can be deleted.
    Last edited by Raner; 03 Dec 2022 at 09:34.
      My Computer

  9. Posts : 38,776
    Win 10 Pro (22H2) (2nd PC is 22H2)

    If you wish to cross-check when doing that with a 3rd party partition manager, and as I showed in the recent thread I mentioned with a screenshot, you can check the creation date of the content of the recovery partitions (rt click , Explore) and delete the oldest ones.
      My Computers

  10. Posts : 18,144
    Windows 11 Pro

    reagentc /disable

    Delete all recovery partitions.
    Easy-peasy, no muss, no fuss, K.I.S.S.

    After the mbr2gpt conversion run:
    reagentc /enable
      My Computer


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