How to Repair EFI Bootloader on a GPT HDD in Windows 7/8/8.1/10?

July 5, 2018

EFI/UEFI not booting on GPT HDD in your Windows 10/8.1/8/7? How can I repair the EFI/UEFI bootloader issue easily and securely, we will guide you to fix it along with various ways.

About EFI/UEFI & Bootloader & GPT & ESP

The UEFI (United Extensible Firmware Interface) is an updated version of BIOS which defines an interface between an operating system and platform firmware. The interface consists of data tables that provide a standard environment for booting an operating system and running pre-boot applications. The UEFI predecessor was EFI (Extensible Firmware interface) which has been deprecated by Intel. UEFI replaces the Basic Input/Output System (BIOS) firmware interface. However, the UEFI/EFI firmware implementations provide legacy support for BIOS services.

EFI

The Bootloader is a program that loads the Windows 10/8/7 operating system or runtime environment for the computer after these self-tests, which makes it to be an essential component of the boot process.

The GPT (Globally Unique Identifiers Partition Table) is a standard for the layout of the partition table on a physical storage device used in a Desktop or server PC. As a part of the UEFI/EFI, it is also used on some BIOS systems due to the limitations of Master Boot Record (MBR).

Besides, Windows 7, 8 and 8.1 could install on a Legacy BIOS using MBR. However Windows 8, 8.1 and 10 were designed to install on the UEFI BIOS using the EFI bootloader and GPT.

The EFI system partition (ESP) is a partition on a data storage device that is used by computers adhering to the EFI/UEFI. The EFI/UEFI firmware will load files stored on the ESP to start Windows operatingsystem and other utilities. It has to be formatted to FAT32.

Preface

Did you meet the EFI boot errors on GPT HDD in your Windows 7/8/10? What did you do? Reinstall Windows operating system could be the first option for majority of users. However, you may suffering the pains from the data loss, like your personal working files, pictures, videos, or design documents installed programs, etc. All of these files and programs spend you a lot of energy and time. Do you want to see your efforts wasted forever? This tutorial will guide you to fix UEFI (EFI) Bootloader problems step by step. In addition, this article is applicable to those Windows operating systems installed on a UEFI BIOS and do the repair of the EFI bootloader on a GPT hard disk drive in Windows 10/8.1/8/7.

How to repair EFI Bootloader on a GPT HDD for Windows 10/8/8.1/7?

There are three ways to fix: Bootrec (only run on Windows 7 OS or previously version), DiskPart, and check errors with AOMEI Partition Assistant Standard. We will guide you with the detailed words:

Bootrec (only works for Windows 7)

A. Insert Windows 7 installation media and boot from it.

B. Press F8 before Windows splash screen appears.

C. Select a language, time, currency, keyboard, or input method, click Next.

D. Choose Repair your computer, then select the Windows 7 and click Next.

E. Choose Command Prompt in System Recovery Options.

F.  Type bootrec.exe and hit enter, then input these commands and run one by one.

bootrec /FixMbr

bootrec /FixBoot

bootrec /ScanOs

bootrec /RebuildBcd

DiskPart: fix UEFI/EFI Bootloader in Windows 7/8/8.1/10

Use DiskPart to fix EFI/UEFI bootloader in Windows 7 is familiar with that in Windows 8/8.1/10 except for the entry of Command Prompt. Thus, following the below steps:

Repair EFI/UEFI Bootloader in Windows 7

Please make sure the Windows 7 UEFI/EFI load with legacy mode is active before you repair UEFI/EFI bootloader.

If you have the Windows installation media, please refer to these words:

1. Input your media to the Windows 7 PC, then boot from the media.

2. Select Repair Your Computer.

3. Choose the operating system and click Next.

4. Select Command Prompt.

5. type these commands and execute one by one:

diskpart

sel disk 0

List vol

6. Check that the EFI partition is using the FAT32 file system and assign a drive letter to this partition, type and run these commands:

sel vol <number of volume>

assign letter=<drive letter>:

exit

7. Type and run the following commands to repair the boot record:

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

bootrec /FixBoot

8. In order to rebuild BCD store, run the following commands:

Ren BCD BCD.old (to backup the old BCD)

bcdboot c:\Windows /l en-us /s <boot letter>: All (note:Add /f between the : and the ALL if you are creating boot entries on an attached USB Flash or other external drive.The C: drive is your system hard drive to boot operating system)

If you don’t have the installation Media, follow these steps to repair EFI/UEFI Bootloader on GPT HDD:

1. Restart your Windows PC and tap rapidly on the F8 key before the Windows splash screen appears.

2. Select Repair your computer->Command Prompt.

The next steps are the same with the Windows 7 Installation media method, which is from the above step 5 to step 8.

Repair EFI/UEFI Bootloader in Windows 8/8.1/10

If you are using Windows 8/8.1/10 and have the Windows installation media in hand, all of the command is the same with the way for how to repair EFI/UEFI bootloader on a GPT HDD in Windows 7 except for the entry to Command Prompt, below is the way to go Command Prompt:

1. Input your media to the Windows 8/8.1/10 PC, then boot from the media.

2. Select Repair Your Computer->Troubleshoot ->Command Prompt.

The next steps are according to the above step 5 to step 8.

If you don’t have the Windows 8/8.1/10 installation Media, follow these steps to repair EFI/UEFI Bootloader on GPT HDD:

1. Restart your Windows 8/8.1/10 PC and tap rapidly on the F8 key before the Windows splash screen appears.

2. Select Repair your computer->Troubleshoot->Command Prompt.

The next steps are the same with the Windows 7 Installation media method, which is from the above step 5 to step 8.

Check errors to repair Windows 10/8.1/8/7 UEFI/EFI Bootloader on GPT HDD

There is another way to do EFI/UEFI bootloader repair, which is create bootable media, then boot from it and check errors for the GPT hard drive. But before that, you have to backup the hard drive with the best free PC backup software-AOMEI Backupper in case of data loss. How to make a bootable media for Windows 10/8.1/8/7? You may need to download the best partition magic software-AOMEI Partition Assistant Standard. This software allows you to make bootable media, resize partition, merge partitions, rebuild MBR, migrate OS to SSD, copy disk, etc. The detailed steps are listed below for making bootable media:

1. Choose an USB flash drive (the capacity should be larger than 13GB) or external hard drive to make bootable media with a normal Windows 10/8/8.1/7 PC, which has the same operating system and EFI/UEFI as yours.

2. Open and run AOMEI Partition Assistant Standard, click Create Bootable Media at the left panel under Wizards.

Make Bootable Media

3. You will get a prompt window, make sure you have noticed already and click Next.

Next

4. There are three options you could choose: Burn to CD/DVD, USB Boot Device, and Export ISO files. We choose USB Boot Device at the step.

USB Boot Device

5. Click Proceed to create Windows 10/8.1/8/7 bootable media in a few minutes.

Tips: The operation will format the USB flash drive or the external hard drive. Therefore, you have to backup your critical data in advance.

6. Boot your corrupted Windows 7/8/8.1/10 PC from the bootable media.

7. Then you could use AOMEI Partition Assistant Standard to check errors in the system hard drive with Disk Surface Test.

Disk Surface Test

8. Or you could rebuild MBR to repair bootloader on GPT hard drive if you ensure the cause be the corrupted MBR.

Rebuild MBR

The EFI/UEFI bootloader problem on a GPT hard drive could be resolved. In addition, AOMEI Partition Assistant provides you the professional edition with command line partitioning, allocate free space, convert MBR to GPT on system disk and vice versa. The server edition supports you to manage your hard disk, migrate OS, and clone your critical data on Windows servers.

Final Words

The ultimate way should be fit for you if these above ways don’t work, which is making a Windows 10/8.1/8/7 installation media then reinstall operating system to fix EFI/UEFI bootloader on a GPT hard drive.