How to Repair the EFI Bootloader on a GPT Hard Drive for Windows

If you’re experiencing issues with your Windows operating system not booting correctly due to problems with the EFI (Extensible Firmware Interface) bootloader on a GPT (GUID Partition Table) hard drive, there are a few steps you can take to try and resolve the issue.

Preparing for the Repair Process

Before attempting to repair the EFI bootloader, it’s important to note that any repairs done to the root of a hard drive have the possibility of going wrong, which could result in the loss of data on the drive that hasn’t been previously backed up. Therefore, it’s always best practice to perform a full backup of the drive before proceeding with any repairs.

Additionally, the repair process will only work for operating systems installed on a UEFI (Unified Extensible Firmware Interface) BIOS. If your system uses a Legacy BIOS, you’ll need to follow a different set of instructions to repair the MBR (Master Boot Record) instead.

Repairing the EFI Bootloader with Installation Media

If you have the Windows installation media (DVD or USB), you can use it to repair the EFI bootloader. Here’s how:

1. Insert the installation media into your computer and restart.
2. Boot from the media.
3. Select “Repair Your Computer” from the menu.
4. Select “Troubleshoot” and then “Advanced Options”.
5. Choose “Command Prompt” from the menu.
6. Type and run the command: diskpart
7. Type and run the command: sel disk 0
8. Type and run the command: list vol
9. Verify that the EFI partition (EPS – EFI System Partition) is using the FAT32 file system and assign a drive letter to it (assign a letter that isn’t already in use):
10. Type and run the command: sel vol <number of volume>
11. Type and run the command: assign letter=<drive letter>:
12. Type and run the command: exit
13. To repair the boot record, type and run the command: cd /d <drive letter>:\EFI\Microsoft\Boot\
14. Type and run the command: bootrec /FixBoot

Repairing the EFI Bootloader without Installation Media

If you don’t have the Windows installation media, you can still attempt to repair the EFI bootloader by booting into the Windows Recovery Environment. Here’s how:

1. Restart your computer.
2. Tap the F8 key rapidly once the computer has turned on, but before the Windows splash screen appears. Be aware that this may take several attempts, as the timing for this option was significantly shortened from Windows 7.
3. Select “Repair your computer” from the menu that appears.
4. Select “Troubleshoot” and then “Advanced Options”.
5. Select “Command Prompt” from the menu.
6. Type and run the command: diskpart
7. Type and run the command: sel disk 0
8. Type and run the command: list vol
9. Verify that the EFI partition (EPS – EFI System Partition) is using the FAT32 file system and assign a drive letter to it (assign a letter that isn’t already in use):
10. Type and run the command: sel vol <number of volume>
11. Type and run the command: assign letter=<drive letter>:
12. Type and run the command: exit
13. To repair the boot record, type and run the command: cd /d <drive letter>:\EFI\Microsoft\Boot\
14. Type and run the command: bootrec /FixBoot

After completing either of the above processes, the next step is to rebuild the BCD (Boot Configuration Data) store. This can be done by running the following command:

bootrec /RebuildBcd

If the above steps don’t resolve the issue, there are a few other things you can try:

• Use the bootrec /ScanOs command to scan for other Windows installations and add them to the BCD store.
• Use the bootrec /RebuildBcd command to rebuild the BCD store from scratch.
• If the above steps still don’t resolve the issue, you may need to perform a clean install of Windows or seek further assistance from Microsoft Support or a qualified technician.

In conclusion, repairing the EFI bootloader on a GPT hard drive for Windows can be a complex process, but with the right steps and a bit of patience, it’s often possible to resolve the issue without needing to perform a clean install of the operating system. By following the instructions outlined above and being cautious when making changes to your hard drive, you should be able to get your system back up and running in no time.