I installed a new disk to my system that dual boots windows 10 and CentOS, I wanted to add the original disk that boots windows 7 to grub, Grub detected an error, I unplug the other disk and attempt to boot windows 7 and find a "Windows failed to start" message that suggests I insert the installation CD. The error specifically mentions that the BCD is unreadable:

File: \EFI\Microsoft\Boot\BCD
Status: 0xc000000d
Info: An error occurred while attempting to read the boot configuration data.

This computer is a Acer I bought pre-assembled so I don't have the CD (I do have an Windows 7 install CD, however). The CD I bought refuses to "Repair Windows" because it wasn't installed from the CD.

I extracted the Windows recovery environment (RE) RE image (winre.wim) from the recovery partition and attempted to make a bootable Windows RE USB using dism on windows 10 (all I have available). I didn't appear in the boot menu, so I had to boot from a WinPE USB I created previously with the RE USB inserted,

ran bootrec /rebuildbcd. It said no windows installation found. I don't know what to do here. Is it possible to make a bootable Windows RE USB? Do I need to make a disk instead? Can I do this without contacting Acer for the retail CD?

to make the bootable Windows recovery environment USB I followed the directions here: https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/apply-images-using-dism

Edit: I used a bootable Windows pre-install environment USB to run chkdsk on the main bootable partition and found no errors (no bad sectors, etc) at all. It doesn't However, I don't know how, but it started working again but broke and displayed the error message again after I re-attached another disk dual-booting CentOS and Win 10. There is an entry for windows 7 in grub but it doesn't work. I think grub is corrupting the BCD file somehow.

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    A possible solution for "no windows installation found". 1) bcdedit /export c:\bcdbackup 2) attrib c:\boot\bcd -h -r -s 3)ren c:\boot\bcd bcd.old 4)bootrec /rebuildbcd . Now it may found it. Try. – NoAngel Nov 15 at 3:35
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    Run Visual BCD editor in winPE, it should be easy to fix this boyans.net – rahuldottech Nov 15 at 7:41
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    Suggestions: (1) If you boot from the CD to Command Prompt, can diskpart see the partition? If yes, you might mark it as active, exit diskpart, and enter bcdboot d:\windows /s d: and bootsect /nt60 all /mbr and reboot. (2) Using the Win7 boot (Window 10 disk disconnected) for starting an installation, does it discover the existing Windows installation? If yes, you might do an "upgrade" to itself. – harrymc Nov 15 at 9:12
  • Sorry, Its using GPT. so I can't use "active". I haven't had a chance to try to the other part as my PC freezes when booting from install disk not to mention its not recognizing bootable USB drives. I have to look in BIOS see if a setting is wrong. – jason dancks Nov 16 at 18:17
  • Too many problems that normally shouldn't happen, unless indeed your BIOS/UEFI is broken, so you might try to reset it or install the latest version (or reinstall the current). If this doesn't help, maybe you should start thinking of a possible hardware problem. – harrymc Nov 18 at 9:50
up vote 1 down vote accepted

It is going to depend on your BIOS settings. If you are in eUFI mode then you will need to edit the eUFI boot menu. I would recommend instead setting it to boot "Legacy mode". Then you can simply point the primary boot device as the drive that contains your Windows OS. When you want to boot to CentOS you would interrupt your boot cycle with the key that brings up the "BBS" or boot drive selector menu (often F8 or F12). Then select the device that has CentOS.

You can add the Linux drive to your BCD menu and your Windows drive to the GRUB menu. That way, no matter what drive it boots to you can choose either OS from either boot menu.

I can't give you more detailed instructions without your motherboard model number but just look up the manual for your motherboard to get the information that matches my description in the BIOS settings.

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