Windows 10 MBR help

Discussion in 'Windows 10' started by bourbon, Dec 14, 2025.

  1. bourbon

    bourbon MDL Novice

    Sep 8, 2012
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    Windows 10 MBR help

    Hopping for some help to resolve my problem as I do not know what to do from the people of this super forum

    The short story

    I have windows 10 installed on a new western Digit 1 TB HDD “few years but hardly used”

    Some time ago I plug the Windows 10 HDD with a USB 3.0 to IDE/SATA connector, connected to my laptop windows 7, booting in to windows 10

    Windows decided to install updates without me knowing at first but it upgraded windows 10 to the last version and deleted the boot manager MBR now it cannot boot

    I am asking for advice on how to Build/ rebuild MBR on windows 10 without losing windows 10 and or everything else?

    The long story

    When windows 10 was offered to upgrade from windows 7 I had a spare HDD with windows 7 and I upgraded to windows 10

    Later I Installed windows 10 to a new western Digit 1TB HDD, I used occasionally as I was using windows 7 and plug in or booted to it as I needed

    My laptop with windows 7,
    The Laptop hard drive was full and showing RED; I wanted to move some files, I plug the Windows 10 HDD with a USB 3.0 to IDE/SATA connector connected to my laptop windows 7 booting in to windows 10, but !

    Microsoft decided to immediately install updates without me knowing it, only realized sometime lather

    The updates; it Upgraded windows 10 to its lust version, it Deleted All my restore point Moved /Deleted some files and other stuff to another partition I cannot see or access the data only taking many GB space and made space to my RED showing hard drive with many GB of free space on it

    Some time ago again I plug in Windows 10 to my laptop with windows 7, and it worked perfect starting windows 10, bout system are on MBR

    Now I got someone to build me a new desktop as my old one died with a used AS Rock x570 Taichi motherboard with lots of HDD connectors, and installed windows 11 Pro last edition on a SPCC M.2 PCIe SSD NVMe 512.1GB (VERY disappointed with windows 11) my gratitude for windows 11; Only Motherboard is Used item.

    I wanted to boot from windows 10 on the new desktop after searching for many days How to change motherboard to start windows with MBR ??

    Windows 10 did not start on the new desktop, it shows the blue repair window asking to repair but No repair option and no other option except to turn it off

    After weeks of try I noted that windows 10 ha no MBR partition, No 100 MB partition at start of the disk, the Upgrade deleted the MBR on windows 10, only realized now, and now it will not boot to my laptop as well, it gives the same error to run repair but no repair backup, and no other option.

    I am looking for advice on the repair, restore MBR on windows 10, and hopefully without losing anything

    Any help much appreciated I do not know much on this problem or anything at all and

    Thank you all

    I may not reply on Monday I am away
     
  2. Logon

    Logon MDL Member

    May 31, 2008
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    Hi, note that if yours is an MBR-style HDD as you describe then it is completely normal that you do not find any 100MB partitions which I guess is an EFI boot partition related to a GPT disk, so just to start please post the status of your HDD as seen by a partitioning program like DiskGenius (portable).
     
  3. bourbon

    bourbon MDL Novice

    Sep 8, 2012
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    #3 bourbon, Dec 22, 2025
    Last edited by a moderator: Dec 22, 2025
    (OP)
    HI! Logon
    Thank You for Your reply, First A very Happy Christmas
    I apologize for a very late reply, I hope your are around a bit longer
    I enclose an image of Disk Management and a Windows 10 start page
    Code:
    Disk 0 (D:) is windows 10, partitioned as storage partition (I:)
    Disk 1, 8 TB is backup disk
    Disk 2, (H:) Windows 7
    Disk 3, (C:) Windows 11, SPCC M.2 PCle SSD 500 GB
    Windows 10 is definitely MBR, not GPT
    I originally installed windows 10 on a desktop with windows 7 and MBR system
    I do not know when the MBR was changed/ deleted, I strongly believe in was done when windows 10 upgraded itself to last version connected to windows 7 computer
    I noted the upgrade too late to stop, I did Not want to upgrade it
    I hope I gave some explanation I do not know what else I can add
    again I thank You for Your reply, I hope to here from you again

    P. S.
    I wasted 3/4 of a day making and wanting to post images but could Not find How to add images on the internet and or this forum Sorry
     
  4. Carlos Detweiller

    Carlos Detweiller Emperor of Ice-Cream
    Staff Member

    Dec 21, 2012
    8,041
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    There are two images, they just don't seem to be public, I guess.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  5. Logon

    Logon MDL Member

    May 31, 2008
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    Exactly.
    It would take less than two minutes to create the related address to post here. :)
     
  6. bourbon

    bourbon MDL Novice

    Sep 8, 2012
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    Dear logon
    HERE Is my page I fund old album "Borbone"
    The third time now I type this message I had to remove all links and
    for security breach
    Borbone's Images

    Move to album
    Select an existing album to move the images.
    You can also create a new album and move the images there.

    Existing album

    Submit

    Borbone
    For forum MDL: Logon
    I had to remove all links so I am adding my logging address for you can
    logging to view images

    The forth time I cannot post anything here
    the album is there and public You may be able to access with last info I gave you Sorry
    I made a new album beside the old one I hope you can see it
    Thank you
     
  7. CaptainKirk1966

    CaptainKirk1966 One of the Green Guys
    Staff Member

    Oct 31, 2009
    2,921
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    #13 CaptainKirk1966, Jan 11, 2026
    Last edited: Jan 11, 2026
    @bourbon - it appears you left out links in that last post. We can not see anything at all. If you are unable to post direct links, alter them a little, maybe substituting hxxp:// for http:// in the links.

    also - Trying to make sense of his thread makes my head hurt. Does anybody have a clue what the OP is talking about? Is it a job for startup repair, fixboot, fixmbr, rebuldbcd, ...

    I've seen separate 50MB system partitions created at the beginning of the disk, and marked as active, with Win 10 installed to bios/mbr format disk. We will never know, unless the OP can provide diskpart or diskmgmt.msc results for us to look at.
     
  8. bourbon

    bourbon MDL Novice

    Sep 8, 2012
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    Existing album
    Borbone'simages (Public)
    Submit
    Embed codes
    Viewer Links
    .... host/signup
    Name borbone
    themail pietrod (delete) 321 (place at) (place a G here) mail (place a dot . here) (comfor comment)
    ThePsWord is barbarosa
    Create to upload image to: MDF

    Please read correct between lines
     
  9. Sajjo

    Sajjo MDL Member

    Feb 6, 2018
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    Sweet Jesus, is it possible to post more cryptic?

    @bourbon
    Feel free to pm me with links and whatnot and i can forward that in a more understandable language.
    This is just ridiculous. (no disrespect :) that is if you'r asking for help)
     
  10. Logon

    Logon MDL Member

    May 31, 2008
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    What we can see is that drive letters are assigned to both partitions on your disk, but the one with the letter D:, which is the one you started Windows from, even if t is correctly Active missing the Boot attribute.

    So, aside from some more probable hypotheses of the cause, as malware, or a disk failure, or a Windows Update suddenly interrupted, what I'm assuming is that you can access those partitions and see their contents, right?

    If so, what I would do as my first step is to use my favorite backup software performing an image back up of the 2 existing partitions on the disk.

    After that, I would boot from a Windows installation USB-DVD media (since you don't seem to be offered any repair options) performing a MBR rebuilt running bootrec.exe commands in sequence, not forgetting to hit Enter after each of them.

    bootrec /fixmbr
    bootrec /fixboot
    bootrec /scanos (this scans your disks for Windows installation, showing that not currently in BCD store)
    bootrec /rebuildbcd

    Please let us know if you think you can be able to both realize and perform the above.

    However, an extremely simpler way would be to run DiskGenius, select your disk, right-click and perform "Rebuild Master Boot Record," but as far as I know that way may not be enough.
     
  11. Logon

    Logon MDL Member

    May 31, 2008
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    Although imaging backup software generally does this before performing, please run a CHKDSK (that's ScanDisk) first.
     
  12. Logon

    Logon MDL Member

    May 31, 2008
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    #19 Logon, Jan 12, 2026
    Last edited: Jan 12, 2026
    bourbon, since yours is an external disk please note that you have to first identify with certainty the letter assigned to your disk at the boot of the Windows installation USB-DVD media before running bootrec.exe, but since I'm not sure if you think you can perform the complete job I would also like to know first if you think you can do it.
    Thanks.


    Edit to add that simplest way for you should be the following.
    From your working Windows open a Command Prompt as administrator and execute the following commands (after making sure that D: is still the correct letter attributed to your disk) pressing Enter after each of them:

    bootrec.exe /fixmbr D:
    bootrec.exe /fixboot D:
    bootrec.exe /rebuildbcd D:

    And that should be all.
     
  13. bourbon

    bourbon MDL Novice

    Sep 8, 2012
    17
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    Dear logon, Sajjo, CaptainKirk1966, Thank You

    As I don't have 5 posts on forum I am not allowed to post links,
    I tried several times typing messages and links for some hours encrypting hiding links to no avail Not even email address and that is the reason for the encrypting

    I almost gave up completely than thinking about your time wasted I told would be a shame to give up like that then I managed to get something to you Finally
    I do apologize for the inconvenience and time consuming on your part Yes taken a lot of time on my part to

    About the windows 10 drive "D:", when plugged into to boot, it is a C:, at moment I connected as a offline drive to get the pictures of it and that is the reason for the driver letter D: , and the C: drive below boot drive win 11
    Regarding your advice I will follow your instructions and I should be able to do it following your steps I will post for any problem / results

    Again I thank you for your help and patience Very Much appreciated Thank You
    You may edit or delete parts, all regarding this !!! post if your wish