Windows 10 - can be my UEFI and MBR conflict?

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  1. Posts : 1,579
    Windows 10 Pro
       #11

    Responses in red.
    After format is ok. No automatic repair. Even when i am changing USB to SDD is fine. But i am on GPT now.

    I installed my Windows 10 in GPT partition. After this Windows 10 updated to new version and downloaded update.
    In bios options i have SSD SAMSUNG and SSD SAMSUNG BOOT MANAGER. Why i have 2 boot of my ssd? What exactly it mean?
    Likely one is suitable for legacy BIOS (MBR suitable boot) and the other is for UEFI boot (the one with BOOT MANAGER).

    2 second question. So before format when i was booting from MBR partition had Automatic repair can you explain me why?

    As stated before - because you were trying to boot an MBR disk as UEFI and there was no information to boot from where UEFI boot was looking, it then probably searched for alternate boot information or a Wndows Boot Manager to use, found it, and then booted on 2nd pass.
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  2. Posts : 246
    Windows 10 Pro
    Thread Starter
       #12

    No i dont had before format WINDOWS BOOT MANAGER in UEFI. I had only 2 boot options in UEFI to choose:P1 SSD SAMSUNG 250 GB ( MBR )and UEFI KINGSTON USB. And after i chang boot from UEFI KINGSTON USB to P1 SSD SAMSUNG 250 GB automatic repair happens only at 1 boot of Windows 10. Then after i click restart from automatic repair screen i was boot to Windows 10 fine. So can you explain me why? Is this because UEFI conflict with MBR?

    It looked like this:
    Attachment 66971
    Last edited by xxx123; 29 Feb 2016 at 07:52.
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  3. Posts : 1,579
    Windows 10 Pro
       #13

    xxx123 said:
    ... Is this because UEFI conflict with MBR?
    Yes. MBR does not have an EFI System Partition.
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  4. Posts : 246
    Windows 10 Pro
    Thread Starter
       #14

    But you looked at screen from bios? ( up )Before format i had only 2 boot options in UEFI to choose:P1 SSD SAMSUNG 250 GB ( MBR )and UEFI KINGSTON USB. And after i change boot from UEFI KINGSTON USB to P1 SSD SAMSUNG 250 GB automatic repair happens only at 1 boot of Windows 10. Then after i click restart from automatic repair screen i was boot to Windows 10 fine. Is this because UEFI conflict with MBR? Or that doesnt matter of Automatic repair ?
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  5. Posts : 1,579
    Windows 10 Pro
       #15

    xxx123 said:
    But you looked at screen from bios? ( up )Before format i had only 2 boot options in UEFI to choose:P1 SSD SAMSUNG 250 GB ( MBR )and UEFI KINGSTON USB. And after i change boot from UEFI KINGSTON USB to P1 SSD SAMSUNG 250 GB automatic repair happens only at 1 boot of Windows 10. Then after i click restart from automatic repair screen i was boot to Windows 10 fine. Is this because UEFI conflict with MBR? Or that doesnt matter of Automatic repair ?
    I did look at all of your screenshots and I still have the user manual for your motherboard.

    I've taken a 2nd look at your manual and there IS an option to use legacy boot through a Compatibility Support Module (CSM) to boot an MBR disk. On the "BOOT" screen, scroll down to items regarding CSM and secure boot. You probably have to disable secure boot to access the legacy boot options. See pages 3-53 and 3-54 in your user manual.

    If booting in UEFI mode, you need a GPT disk scheme (which would have a 100 MB or so EFI System Partition) to boot with.

    MBR disk scheme has NO EFI System Partition. You can call it "conflict" but it's more like you're mixing apples and oranges.

    The UEFI boot of the MBR scheme disk has already passed from your BIOS to Windows control when it fails - the resolution and 2nd boot is accomplished by Windows finding in the repair routine what it needs to boot - and NOTHING in your BIOS/EFI firmware has been changed. So, then if you close Windows and reboot from your BIOS/EFI, you keep having the same result.
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  6. Posts : 246
    Windows 10 Pro
    Thread Starter
       #16

    Word Man said:
    I did look at all of your screenshots and I still have the user manual for your motherboard.

    I've taken a 2nd look at your manual and there IS an option to use legacy boot through a Compatibility Support Module (CSM) to boot an MBR disk. On the "BOOT" screen, scroll down to items regarding CSM and secure boot. You probably have to disable secure boot to access the legacy boot options. See pages 3-53 and 3-54 in your user manual.

    If booting in UEFI mode, you need a GPT disk scheme (which would have a 100 MB or so EFI System Partition) to boot with.

    MBR disk scheme has NO EFI System Partition. You can call it "conflict" but it's more like you're mixing apples and oranges.

    The UEFI boot of the MBR scheme disk has already passed from your BIOS to Windows control when it fails - the resolution and 2nd boot is accomplished by Windows finding in the repair routine what it needs to boot - and NOTHING in your BIOS/EFI firmware has been changed. So, then if you close Windows and reboot from your BIOS/EFI, you keep having the same result.
    Explain me please why at 1 boot windows get Automatic repair. On screen with automatic repair i click restart and then windows boot fine. So needed 2 boots.Is this someting with bios related what you are talking about? Or cause was elsewhere?

    This is answer yes? Can you explain more brighter? :"The UEFI boot of the MBR scheme disk has already passed from your BIOS to Windows control when it fails - the resolution and 2nd boot is accomplished by Windows finding in the repair routine what it needs to boot - and NOTHING in your BIOS/EFI firmware has been changed. So, then if you close Windows and reboot from your BIOS/EFI, you keep having the same result."


    So this is issue with disk or only bios?
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  7. Posts : 1,579
    Windows 10 Pro
       #17

    No, I don't think I can explain more brighter as I've tried to explain it about 8 different ways.

    It's all BIOS/UEFI, MBR/GPT, Windows related.

    1) MBR disks must be booted by legacy BIOS (which is an option I've pointed out how to accomplish on your motherboard).

    2) UEFI booting requires a GPT disk. This is why Windows has to fix itself and only boots in 2nd cycle - as you keep trying to boot UEFI to an MBR disk.

    I recommend you make up your mind whether to set up your disk as MBR or GPT and then set your BIOS boot options (in manner I have already explained to you) to either boot legacy (if MBR chosen) or boot UEFI (if GPT chosen).

    I highly recommend you choose UEFI secure boot to a GPT disk scheme - which it looks like you are currently doing.
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  8. Posts : 246
    Windows 10 Pro
    Thread Starter
       #18

    1.After formatted disk to GPT partition scheme i am booting Windows 10 from: SSD SAMSUNG 250 BOOT MANAGER in UEFI. No problems with this, system booting properly once without Automatic repair . So last time , why it was booting two times ( 1 boot was automatic repair ) after closing system? ( Parition was on MBR )



    2.I dont change anything in UEFI SECURE BOOT , all is on default:)




    3.Somebody said to me this:"
    UEFI firmware can emulate BIOS functionality (CSM/Legacy) and work with MBR disks just fine." But you said:"UEFI booting requires a GPT disk. This is why Windows has to fix itself and only boots in 2nd cycle - as you keep trying to boot UEFI to an MBR disk." So why i had automatic repair during 1 boot?
    Last edited by xxx123; 29 Feb 2016 at 10:33.
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  9. Posts : 1,579
    Windows 10 Pro
       #19

    xxx123 said:
    1.After formatted disk to GPT partition scheme i am booting Windows 10 from: SSD SAMSUNG 250 BOOT MANAGER in UEFI. No problems with this, system booting properly once without Automatic repair . So last time , why it was booting two times ( 1 boot was automatic repair ) after closing system? ( Parition was on MBR )...
    Because you can't boot UEFI to an MBR disk, as I've stated repeatedly. Closing system does NOTHING to resolve the conflict that you have attempting to boot UEFI on an MBR disk. The repair was having NO effect on the BIOS and it shouldn't - it's strictly a Windows function - and Windows simply found an alternate way to boot, it did NOT create an EFI System Partition for you.

    xxx123 said:
    ...2.I dont change anything in UEFI SECURE BOOT , all is on default:)......
    Good. You should keep your disk in a GPT partition scheme then.

    xxx123 said:
    ...3.Somebody said to me this:" UEFI firmware can emulate BIOS functionality (CSM/Legacy) and work with MBR disks just fine." ...
    I explained to you that your firmware can indeed emulate BIOS functionality AND I pointed you to the specific pages in your user manual that explained to you how to take advantage of that capability - did you read it? - Post #15.

    xxx123;585114...[COLOR=#000000 said:
    But you said:"UEFI booting requires a GPT disk. This is why Windows has to fix itself and only boots in 2nd cycle - as you keep trying to boot UEFI to an MBR disk." So why i had automatic repair during 1 boot?
    I think we're going in circles on this one. Exactly what is it you don't understand about: You passed control to Windows and Windows fixed itself but did nothing to fix the fact that you were repeatedly trying to boot UEFI with an MBR disk?
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  10. Posts : 246
    Windows 10 Pro
    Thread Starter
       #20

    SO before i mark thread as solved so this is not hardware issue?
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