Convert MBR to GPT - MBR2GPT fails with error 0x00000000

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  1. Posts : 14
    Windows 10 Pro
       #1

    Convert MBR to GPT - MBR2GPT fails with error 0x00000000


    I've been trying to convert my OS drive from MBR to GPT for 3 days so I can enable secure boot. OS is windows 10 Pro, 21H2. Laptop is a Samsung NP930X5J. Original SSD was 256 GB; I imaged it to a 1TB SSD many years ago using Acronis, replicating the whole disk (4 partitions), expanding the main partition to fill the larger SSD. System has been working trouble-free for ~8 years. Original system was Windows 8.1 pro, upgraded to Windows 10 pro a long time ago. No dual-boot, nothing fancy at all.

    When I first ran the following command: mbr2gpt /validate /allowOSfull I got "Disk layout validation failed for disk 0". After days of experimenting, I eliminated one of the 4 partitions (a 100MB partition that had virtually nothing in it) and after that, I was able to get a 'validation completed successfully'.

    So then I tried mbr2gpt /convert /allowfullOS. The command failed with this error:

    Code:
    C:\WINDOWS\system32>mbr2gpt /convert /allowfullOS
    
    MBR2GPT will now attempt to convert the default book disk.
    If conversion is successful the disk can only be booted in GPT mode.
    These changes cannot be undone!
    
    MBR2GPT: Attempting to convert disk 0
    MBR2GPT: Retrieving layout of disk
    MBR2GPT: Validating layout, disk sector size is: 512 bytes
    MBR2GPT: Trying to shrink the OS partition
    MBR2GPT: Creating the EFI system partition
    MBR2GPT: Installing the new boot files
    MBR2GPT: Performing the layout conversion
    Cannot perform layout conversion. Error: 0x00000000
    MBR2GPT-undo: Removing the EFI system partition
    MBR2GPT-undo: Extending back the OS partition
    MBR2GPT: Conversion failed
    System boots fine into Windows 10 in this configuration; I just can't convert to GPT.

    I'm now heading down the rabbit-hole of pursuing the 0x00000000 error, but would appreciate any insight from anyone out there! Thanks.
      My Computers


  2. Posts : 23,422
    Win 10 Home ♦♦♦19045.4412 (x64) [22H2]
       #2

    Hello @Steerpike58, welcome to TenForums.

    Please post a screenshot of Disk Management, as shown below...

    How to Post a Screenshot of Disk Management
      My Computer


  3. Posts : 14
    Windows 10 Pro
    Thread Starter
       #3

    Ghot said:
    Hello @Steerpike58, welcome to TenForums.

    Please post a screenshot of Disk Management, as shown below...
    Thanks for following up! Here is a screenshot from Disk management:

    Convert MBR to GPT - MBR2GPT fails with error 0x00000000-diskmgmt-imaged-1tb-ssd-oldersamsung-postconversion6.jpg

    The 16 GB OEM Partition was originally labeled 'SAMSUNG_REC' and contained a bunch of Samsung stuff. The 525 MB 'Recovery Partition' contained only 'recovery' folder. I'm willing to lose those partitions, though I'd like to still have the ability to go to Settings / update and security / recovery / advanced startup, and have troubleshoot / Advanced options / Command prompt available, if possible (they ARE available now). I believe they rely on some of those partitions being available. I can no longer use F4 on boot to directly enter the recovery console.

    Edit To Add: found this post that provides a very detailed solution, though it seems specific to Dell. I get the sense my issues are relating to the Samsung recovery stuff that was there from the beginning. Is it possible to recreate a 'recovery' partition 'after the fact'? MBR2GPT conversion 0x00000000 Error - General Hardware Forum.
      My Computers


  4. Posts : 23,422
    Win 10 Home ♦♦♦19045.4412 (x64) [22H2]
       #4

    Steerpike58 said:
    Thanks for following up! Here is a screenshot from Disk management:

    Convert MBR to GPT - MBR2GPT fails with error 0x00000000-diskmgmt-imaged-1tb-ssd-oldersamsung-postconversion6.jpg

    The 16 GB OEM Partition was originally labeled 'SAMSUNG_REC' and contained a bunch of Samsung stuff. The 525 MB 'Recovery Partition' contained only 'recovery' folder. I'm willing to lose those partitions, though I'd like to still have the ability to go to Settings / update and security / recovery / advanced startup, and have troubleshoot / Advanced options / Command prompt available, if possible (they ARE available now). I believe they rely on some of those partitions being available. I can no longer use F4 on boot to directly enter the recovery console.

    Edit To Add: found this post that provides a very detailed solution, though it seems specific to Dell. I get the sense my issues are relating to the Samsung recovery stuff that was there from the beginning. Is it possible to recreate a 'recovery' partition 'after the fact'? MBR2GPT conversion 0x00000000 Error - General Hardware Forum.



    It may be the OEM partition.

    Have you tried to do the conversion with Minitool Partition Wizard (free)?

    Best Free Partition Manager for Windows | MiniTool Partition Wizard Free


    How to...
    How to Convert MBR to GPT without Data Loss in Windows 7/8/10




    Be VERY careful. No matter the guarantees, there's always a chance of data loss.
    I wouldn't try this conversion with ANY method, without having a full OS backup.


    I messaged a guy that may be able to help. He's offline at the moment.
    He'll be on tomorrow if not sooner.
      My Computer


  5. Posts : 4,619
    several
       #5

    Is it possible to recreate a 'recovery' partition 'after the fact'?
    is the full model number of your laptop Samsung NP930X5J ?

    I think there was a program for doing that , but iirc there were several versions of samsung recovery solutions.

    it is called admin tools for samsung recovery.
    Last edited by SIW2; 11 Mar 2023 at 23:25.
      My Computer


  6. Posts : 14
    Windows 10 Pro
    Thread Starter
       #6

    Ghot said:
    It may be the OEM partition.

    Have you tried to do the conversion with Minitool Partition Wizard (free)?

    Best Free Partition Manager for Windows | MiniTool Partition Wizard Free

    How to...
    How to Convert MBR to GPT without Data Loss in Windows 7/8/10

    ...
    I have been trying with MiniTool Partition Wizard (Free) but - as soon as I select the mbr2GPT option, up pops the screen to get me to license the 'professional' version. Tried several times. So the fact that their guide says you can do this with 'free' version seems to be incorrect, unless I'm missing something! I believe I tried AOMEI's free version also; same issue.

    EDIT TO ADD: I don't mind paying $59 for the tool but it says the license is for '1 PC'. I have two identical PCs, and all I want to do it convert them to GPT so I'd prefer not to pay $59 twice, just for this feature. If by '1 PC' they mean, concurrently, then I can do one then the other but if they are super strict about it, could be a pain.

    My actual goal here is to take one of my old Samsung NP930X5J's (which have been rock-solid) and use it as a test bed for upgrading to, and then playing with, W-11. I already have 2 new W-11 laptops but I want a third to really 'experiment' destructively on!

    - - - Updated - - -

    SIW2 said:
    is the full model number of your laptop Samsung NP930X5J ?

    I think there was a program for doing that , but iirc there were several versions of samsung recovery solutions.

    it is called admin tools for samsung recovery.
    The full, full model number is NP930X5J-S01US, but the last bits denote things like SSD size, ram size, etc. There were two main models in the family - NP930 and NP940. The 940's had touchscreens, the 930's did not. X5J's were 15.6" screens.

    For a time, Samsung had a really good 'download' site for this model but now it's long gone.
      My Computers


  7. Posts : 4,619
    several
       #7

    It can be done with diskgenius free versiosn.

    It is not automated. You need to run it from another os ( or winpe) point it at the disk and convert to gpt.

    Then use it create an esp partition in unallocated space. Then run bcdboot command to populate the esp partition with the boot files.

    I have done it several times only takes a couple of minutes.

    I have never tried it on something with a weird partition id like yours seems to have.

    there is probably a giveaway of one year license for aomei partition assistant pro if you look around. I have used that a couple of times without any problem.
      My Computer


  8. Posts : 4,619
    several
       #8

    here:
    AOMEI Partition Assistant Pro ? ?????????? ????????

    if you already have version 9.15.0 installed, just enter the key provided at that page.
    apparently it lasts forever, but only gets upgrades till the end of the year.

    looks like the registration period has expired.
      My Computer


  9. Posts : 6,392
    Windows 11 Pro - Windows 7 HP - Lubuntu
       #9

    Managing and playing with partitions is a risky task. Create a drive image before you begin.

    To convert the drive from Legacy - MBR to UEFI - GPT your laptop must have UEFI BIOS. If it does, why it didn't came as UEFI - GPT?

    Are you sure the Laptop has UEFI BIOS?

    On a conversion from Legacy - MBR to UEFI - GPT, you convert the drive from MBR to GPT and create a FAT32 UEFI partition with the boot manager.

    As SIW2 has mentioned you can boot from a WinPE drive, convert the main drive to GPT and then create a FAT32 UEFI partition with the boot manager.

    Another solution is:
    - Create a drive image of the main drive and save it on an external drive.
    - Boot a Win 10 USB installation drive as UEFI, delete all partitions on the drive and do a Clean Install . This will convert the drive from MBR to GPT and install Windows as UEFI-GPT. It will have all the partitions:
    - EFI - FAT32 - 100M
    - MRS - RAW - 16M
    - C: NTFS partition
    - Recovery - NTFS - 650M
    - Run the drive image software and replace the Win 10 partition (the one you just created) with the one on the drive image you created early.

    It will boot your current Widows as UEFI-GPT.
      My Computers


  10. Posts : 15,498
    Windows10
       #10

    MBR2GPT is very temperamental when trying to do it from running windows. It is much more reliable from WinPE mode.

    https://learn.microsoft.com/en-us/wi...ent/mbr-to-gpt

    I would try this:-

    Boot from a Windows 10 usb installation drive and press shift+f10 at first screen to get to command prompt.

    then type

    Code:
    MBR2GPT /validate /disk:0
    If it validates ok, then do this

    Code:
    MBR2GPT /convert /disk:0
    Once finished, cancel Windows installation and reboot pc. PC must be set to boot from UEFI of course.

    I recommend you make an image backup first. If you use Macrium Reflect to make image, you can boot from its Rescue drive to get to a command prompt, clicking on c:> icon in botom left corner and run mbr2gpt from there if you prefer.
      My Computer


 

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