Windows boot sequence

Discussion in 'Windows 10' started by DOStiger, Oct 7, 2023.

  1. DOStiger

    DOStiger MDL Novice

    Oct 3, 2023
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    Hi,

    I'm wondering how to make a Windows partition bootable.

    Some background (skim to "The problem" paragraph if you're impatient):

    My Windows install started as Win7 Pro which came with my DELL Precision M6600 laptop some time in 2011. I used it as my main OS until December 2019, when I switched to Linux Mint.

    On Linux, I installed VMware Player, and set up my Win7 install as a virtual machine using the physical, pre-existent hard disks directly. I upgraded it to Win10 in May 2023.

    In September, I bought a new Lenovo ThinkPad P16 Gen.2, installed Linux Mint on it, and set up the Windows VM from the DELL Precision on it. The main difference is that I am now running the VM with VMDK disk images rather than the physical harddisk.

    The problem is that the main Windows partition was never directly bootable. On the DELL Precision, it booted via a hidden DELL partition. On my ThinkPad, I had to boot from the Win10 installation media (a USB flash drive), and I used "startup repair", which made the VM bootable via the install medium (which I made into a VMDK). If I remove the "install" disk, the VM will not boot.

    In the good old days, with DOS and Win9x, you could run "sys c:" to make drive C: into a bootable partition. Sometimes, you would also have to run "fdisk /mbr", but that was all. How can I do this on Windows 10?

    /DT
     
  2. DOStiger

    DOStiger MDL Novice

    Oct 3, 2023
    11
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    This may be useful information:

    Code:
    C:\Windows\System32>bcdedit
    
    Windows Boot Manager
    --------------------
    identifier              {bootmgr}
    device                  partition=F:
    path                    \bootmgr
    description             Windows Boot Manager
    locale                  en-GB
    default                 {current}
    displayorder            {current}
    timeout                 30
    
    Windows Boot Loader
    -------------------
    identifier              {current}
    device                  partition=C:
    path                    \Windows\system32\winload.exe
    description             Windows 10 Pro
    locale                  en-GB
    osdevice                partition=C:
    systemroot              \Windows
    resumeobject            {e3f7bde9-57c2-11ee-93f8-806e6f6e6963}
    bootmenupolicy          Standard
    hypervisorlaunchtype    Auto
    
     
  3. Tito

    Tito Super Mod / Adviser
    Staff Member

    Nov 30, 2009
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    #3 Tito, Oct 7, 2023
    Last edited: Oct 7, 2023
    @DOStiger

    Boot the target VM with a Windows PE/Windows installation media, spawn Command Prompt (Shift + F10), and post the output of the following commands:
    Code:
    diskpart
    
    list disk
    
    select disk 0 [provided there is only one virtualized disk in the VM]
    
    list partition
    
     
  4. Tito

    Tito Super Mod / Adviser
    Staff Member

    Nov 30, 2009
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    #5 Tito, Oct 7, 2023
    Last edited: Oct 7, 2023
    @DOStiger

    I believe the 449 GB one is the virtualized copy of the Windows 10 HDD (that was upgraded from Windows 7) from the Dell laptop? If so, then what's the role of the 14 GB sized second disk? Is it a 16 GB USB storage or similar that you passed to the guest from the host?

    Anyway, as suspected, Windows is installed in MBR style, which means you just needs to mark the partition as active and write the proper master boot code to make it bootable.

    Repeat the same sequence of commands and the do this next:
    Code:
    select partition 1
    active
    
    After a successful completion, type "exit" to end from Diskpart session. Then, proceed with the restoration of the boot sector:
    Code:
    bootsect /nt60 sys
    
     
  5. acer-5100

    acer-5100 MDL Guru

    Dec 8, 2018
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    That's obviously not needed

    You need to do that only if you want to switch from ntldr to bootmgr
     
  6. DOStiger

    DOStiger MDL Novice

    Oct 3, 2023
    11
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    Yes it is.

    It is a disk image created from a USB flash drive containing the Windows 10 installation files. The role of this disk is to pass control to the 449 GB disk/partition.

    I want to be able to boot directly from the 449 GB partition.

    I had to use "bootsect /nt60 c:" to target the correct partition.

    Alas, on trying to boot from this (449 GB) partition, the system freezes with a blinking cursor and not responding to Ctrl+Alt+Del.

    /DT
     
  7. acer-5100

    acer-5100 MDL Guru

    Dec 8, 2018
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    forget bootsect

    You need just to set the partition you want to boot from as active

    and install the bootloader configuration files using

    bcdboot

    That's all
     
  8. DOStiger

    DOStiger MDL Novice

    Oct 3, 2023
    11
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    I ran "bcdboot C:\Windows /s c:", and it completed successfully with the message "Boot files successfully created".

    However, when I try to boot from the partition, it hangs with a blinking cursor and not responding to Ctrl+Alt+Del.

    /DT
     
  9. atgpud2003

    atgpud2003 MDL Addicted

    Apr 30, 2015
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    Sound like MBR sector issues??

    ATGPUD2003
     
  10. acer-5100

    acer-5100 MDL Guru

    Dec 8, 2018
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    Sorry but I missed your reply.

    In rare cases the partition table becomes messed at the point that no matter what you do that partition stay unbootable.

    In such case, you can workaround shrinking slightly the partition, adding a small one at the end, making it active and installing the boot files there (using bcdboot)

    Or copy your partition using ESUS/Paragon/Acronis/whatever partitioning SW, to a new virtual disk, make it active and reinstall the boot files.

    This always works but is obviously more time consuming and requires some additional temporary space.
     
  11. DOStiger

    DOStiger MDL Novice

    Oct 3, 2023
    11
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    I already have something similar set up, and I noted in my opening post. In short, it's the installation USB disk turned into a VMDK. See: https://forums.mydigitallife.net/threads/windows-boot-sequence.87555/#post-1809230
    It appears the "bootmgr" is not installed on C:.

    /DT
     
  12. acer-5100

    acer-5100 MDL Guru

    Dec 8, 2018
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    The standard installation done via old school setup never installs the boot files on C:.

    It's meant to allow boot if the C drive is encrypted. Something desiderable in corporate environments, and in general for mobile users that can forget somewhere the notebook or may have it stolen.

    But hardly needed for normal home PCs.