You can repairing the EFI (Extensible Firmware Interface) Bootloader on a GPT (GUID [Globally Unique Identifiers] Partition Table) Hard Disk Drive in Windows 10 and this solution only works for OSs installed on a UEFI (Unified Extensible Firmware Interface) BIOS (Basic Input/Output System). You know, most people with boot issues on Windows Operating Systems choose to reinstall the operating system rather than attempt to fix the boot issue itself.

How to repair your EFI Bootloader Windows 10

The GPT structure deals with many of the problems that the Bootsect command was designed to remedy in MBR. However, if you must repair the EFI bootloader, follow the appropriate instructions below:

If you do have the Installation Media:

  1. Insert the Media (DVD/USB) in your personal computer and restart.
  2. Boot from the media.
  3. Select Repair Your Computer.
  4. Select Troubleshoot.
  5. Select Advanced Options.
  6. Choose Command Prompt from the menu:
    1. Type and run the command:

      diskpart

    2. Type and run the command:

      sel disk 0

    3. Type and run the command:

      list vol

  7. Verify that the EFI partition (EPS – EFI System Partition) is using the FAT32 file system. Assign a drive letter to it that is not already in use.):
    1. Type and run the command:

      sel vol <number of volume>

    2. Type and run the command:

      assign letter=<drive letter>:

    3. Type and run the command:

      exit

  8. In order to repair the boot record:
    1. Type and run the command:

      cd /d <drive letter>:\EFI\Microsoft\Boot\

    2. Type and run the command:

      bootrec /FixBoot

Note: If your Operating System installation media is Windows 10 (version 1709 or newer) please ignore the commands in step 8, and go straight to the information at the end of this section of instructions.

If you do not have the Installation Media:

  1. Restart your personal computer.
  2. Tap rapidly on the <F8> key once the personal computer has turned on, but before the Windows Splash Screen appears.

    Be aware this may take several attempts. The timing for this option was shortened from that in Windows 7.

  3. Select Repair your computer from the menu that appears.
  4. Select Command Prompt from the Advanced Options tab in the Troubleshoot screen:
    1. Type and run the command:

      diskpart

    2. Type and run the command:

      sel disk 0

    3. Type and run the command:

      list vol

  5. Verify that the EFI partition (EPS) is using the FAT32 file system and assign a drive letter to it that is not already in use:
    1. Type and run the command:

      sel vol <number of volume>

    2. Type and run the command:

      assign letter=<drive letter>:

    3. Type and run the command:

      exit

  6. In order to repair the boot record:
    1. Type and run the command:

      cd /d <drive letter>:\EFI\Microsoft\Boot\

    2. Type and run the command:

      bootrec /FixBoot

The next step is the same across all the operating systems:

  1. Rebuild the BCD store.
    1. First run the command below to back up the old BCD:

      ren BCD BCD.old

    2. Now re-create it using this command:

      bcdboot c:\Windows /l en-us /s <boot letter>: All

Note: If you are creating boot entries on an attached USB Flash or other external drive, add /f between the: and the ALL. Remember that the <boot letter> is replaced with the letter of the drive that you are booting from. (For example, C:\, D:\)

 

Note: If your Operating System media is Windows 10 (version 1709 or newer) use the following command instead of the last set of steps:

  • c:\Windows /s <boot letter>: /f UEFI

How to repair your MBR (Main Boot Record)

These steps apply to any legacy drive used as a boot drive on any recent Windows Operating System.

  1. Use the F12 key at the Dell Splash screen to enter the boot menu. It lets you boot from the Windows installation media or a bootable disk or flash drive.
  2. Click the Repair your Computer link at the bottom of the Install Now screen.
  3. Click Troubleshoot.
  4. Select Command Prompt
  5. Enter the following three commands in turn, following each by pressing the Enter key:

    bootrec /fixmbr

    bootrec /fixboot

    bootrec /rebuildbcd

  6. Restart the computer with the installation media removed to check if the repair worked.

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