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windows:client_os:uefi_repair [2019/10/31 09:06] (current)
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 +====== Repair UEFI Bootloader in Windows 8 ======
 +The corruption of the Windows 8 bootloader can, occur after the installation of the second OS (in Dual Boot configurations),​ be caused by the erroneous actions while failure recovering and for some other reasons. If the loader in Windows 8 on UEFI system is corrupted, it’s impossible to start the system or a blue screen with the following error appears:
 +The boot configuration data for your PC is missing or contains errors.
 +File :​\EFI\Microsoft\Boot\BCD
 +Error code: 0xc000000f
 +All this can imply corruption or even total removal of Windows 8 loader configuration – Boot Configuration Data (BCD). You won’t be able to recover the BCD loader using bcdedit. When running this command, the following error appears:
 +The boot configuration data store could not be found.
 +The requested system device cannot be found
 +The matter is that the BCD loader configuration in Windows 8 installed in UEFI mode is stored on a separate hidden EFI volume (100 MB in size on FAT32 file system). Bcdedit can not see it and, therefore, manage the loader configuration on it.
 +So to recover the loader (BCD) configuration,​ you have to boot from the original installation Windows 8 DVD (or a recovery disk or a special EFI bootable flash drive) and open the command line choosing System Restore – > Troubleshoot->​ Command Prompt or pressing Shift+F10).
 +  - Start diskpart:
 +  - Display the list of disks in the system:
 +  - Select the disk with Windows 8 installed (if there is one disk in the system, it will have zero index):
 +  - Display the list of volumes in the system:
 +    * It can easily be recognized by its size of 100 MB and FAT32 file system
 +  - Select the volume
 +  - Assign any disk letter to the EFI volume:
 +  - Close diskpart:
 +  - Go to the bootloader directory in the hidden volume
 +  - Recreate the boot sector on the boot partition
 +  - Delete the current BCD configuration file by renaming it (save the older configuration as a backup):
 +  - With bcdboot.exe,​ create BCD store again by copying the boot files from the system directory:
 +    * where C:\Windows – is the path to the directory with Windows 8 installed.
 +    * /f ALL – means that the boot files have to be copied including those for UEFI and BIOS computers (potential ability to boot in EFI and BIOS systems)
 +    * /l en-us – is a type of the system locale. By default, en-us – English (USA) is used.
 +  - Now you have to restart your computer. Then in the list of bootable devices there appears Windows Boot Manager where you can choose desired operating system to start.
 +  - diskpart
 +  - list disk
 +  - sel disk 0
 +  - list vol
 +  - select volume 1
 +  - assign letter K:
 +  - exit
 +  - cd /d k:​\efi\microsoft\boot\
 +  - bootrec /fixboot
 +  - ren BCD BCD.bak
 +  - bcdboot C:\Windows /l en-us /s k: /f ALL
windows/client_os/uefi_repair.txt · Last modified: 2019/10/31 09:06 (external edit)