{"id":32027,"date":"2023-01-17T18:41:45","date_gmt":"2023-01-17T13:11:45","guid":{"rendered":"http:\/\/198.58.113.91\/blog\/?p=32027"},"modified":"2024-04-17T12:34:12","modified_gmt":"2024-04-17T07:04:12","slug":"rebuild-efi-partition-bcd-boot-files","status":"publish","type":"post","link":"https:\/\/www.winhelponline.com\/blog\/rebuild-efi-partition-bcd-boot-files\/","title":{"rendered":"How to Rebuild the EFI Boot Partition, BCD and Boot Files"},"content":{"rendered":"

The EFI boot partition is a FAT32 partition that stores the boot files and the boot configuration data (BCD) to load Windows. Sometimes, the boot partition or the BCD may get corrupted, and the boot files remain unserviceable by the Windows Setup process. In that case, rebuilding the EFI partition and recreating the BCD & boot files should resolve the issue.<\/p>\n

Although rebuilding the EFI is easy, I advise creating an image backup (using Macrium Reflect or similar utilities) of your complete system, especially if you’re new to Windows RE and DiskPart. This is because it can be risky if you inadvertently type an incorrect drive-letter or volume # in DiskPart.<\/em><\/p>\n

And, of course, the drive letters and Volume numbers used in this article are valid only for this computer. The drive-letters and volume # in your computer will vary depending on your disk layout.<\/p>\n

Also, this article applies only for UEFI-based computers. If you’re using legacy boot\/MBR disk, this article doesn’t apply. See How to Find if a Disk Uses MBR or GPT<\/a><\/em><\/p>\n

The below demonstration was done from a Windows 11 computer.<\/p>\n

Rebuild the EFI Partition, BCD, and Boot Files<\/h2>\n

1] Boot into Windows RE<\/h3>\n

Boot into the native Windows Recovery Environment (WinRE). To do so, click Start, click on the Power button, press and hold the Shift key down, and click Restart.<\/p>\n

This starts the Windows Recovery Environment.<\/p>\n

Alternatively, on the Windows sign-in screen, press and hold the Shift key while you select Power \u2192 Restart.<\/p>\n

RELATED:<\/strong> See Different ways to access the Windows Recovery Environment (WinRE)<\/a><\/em><\/p>\n

(If the native WinRE can’t be enabled on your computer, you can create a bootable USB setup disk<\/a> and boot it into WinRE.)<\/em><\/p>\n

In Windows RE, click Troubleshoot \u2192 Advanced Options \u2192 Command Prompt<\/strong>.<\/p>\n

\"windows<\/p>\n

\n

2] Find the OS Partition’s Drive-letter<\/h3>\n

In Command Prompt, type bcdedit<\/strong> and press Enter.<\/p>\n

Note down the drive letter of your Windows installation.<\/p>\n

Hint:<\/strong> Look at the “device<\/code>“, “description<\/code>“, “osdevice<\/code>“, and “path<\/code>” (winload.efi<\/strong>) values to determine the Windows partition.<\/em><\/p>\n

\"bcdedut<\/p>\n

In the above example, the Windows drive letter (when seen from native WinRE) is E:<\/strong><\/em><\/p>\n

\n

3] Assign a drive-letter for the EFI partition<\/h3>\n

Type DiskPart<\/strong> and press Enter.<\/p>\n

In the DiskPart environment, type list volume<\/strong>\u00a0 (or “lis vol<\/strong>” for short.)<\/p>\n

Note down the volume number of the EFI partition. If the EFI partition doesn’t have a volume label, you can identify the partition by its file system and size.<\/p>\n

(Hint:<\/strong> The EFI partition uses the FAT32<\/strong> file system. Typically, the EFI partition’s size will be in the range of 100 MB to 500 MB, although 500 MB is certainly not<\/strong> a mandatory upper limit. On some systems, the EFI partition may show up as “RAW” instead of “FAT32” and the boot files may be inaccessible. It again indicates a corrupt partition.)<\/em><\/p>\n

\"diskpart<\/p>\n

Once you have identified the Volume # of the EFI partition, which in this case, is “Volume 3”, type the following command:<\/p>\n

select volume 3<\/strong><\/pre>\n
And then type:<\/p>\n
assign letter=y<\/strong><\/pre>\n
You should see the output:\u00a0“DiskPart successfully assigned the drive letter or mount point.”<\/em><\/p>\n
You’ve now assigned the EFI partition a drive letter (Y:<\/code>)<\/p>\n
Now, run the following command to fix the EFI partition’s identifier:<\/p>\n
(Note:<\/strong> The following command-line doesn’t appear in the above screenshot. But it’s recommended to run it.)<\/em><\/p>\n
set id=c12a7328-f81f-11d2-ba4b-00a0c93ec93b<\/pre>\n
The above step ensures that the EFI partition’s identifier is correctly set. The identifier c12a7328-f81f-11d2-ba4b-00a0c93ec93b represents the EFI system partition. Reference: Fix the EFI Boot Partition’s ID<\/a>.<\/em><\/p>\n
Type exit<\/strong> to quit the DiskPart environment.<\/p>\n
\n
Tip:<\/strong> To cross-verify if Y:<\/code> or Volume 3<\/code> in this example is the EFI boot partition, run the DIR Y:<\/strong> command. You should see a directory named EFI<\/strong>.\"efi<\/p>\n<\/div>\n
\n
4] Backup the BCD and Boot Files (Optional step)<\/h3>\n
Next, let’s backup the boot files and the BCD database to a different location on the hard drive — to E:\\, which is your Windows partition in this example. This is an optional<\/strong> step anyway.<\/p>\n
\nNote:<\/strong> Skip<\/strong> this step if your EFI partition’s file system shows up as RAW instead of FAT32. Because the command will fail with error code 1005<\/code> (0x000003ED<\/code>) when run on a RAW partition.<\/p>\n
\"EFI<\/p>\n<\/div>\n
In the Command Prompt window, type:<\/p>\n
robocopy Y:\\EFI  E:\\EFI.BAK \/MIR \/R:1 \/W:1<\/pre>\n
\"robocopy<\/p>\n
The boot files and the BCD are now backed to the E:\\ drive.<\/p>\n
\"robocopy<\/p>\n
The summary shows that every file and folder has been copied (mirrored) to the E:\\EFI.BAK<\/code> directory.<\/em><\/p>\n
NOTE:<\/strong> If the above Robocopy command gets stuck in a loop, press Ctrl<\/strong> + C<\/strong> to stop its execution. Proceed to the next step in this article.<\/p>\n
\n
Tip:<\/strong> In addition to the above, you can individually <\/strong>backup the boot configuration database (BCD) file to another location if you want. To do so, run this command:<\/p>\n
bcdedit \/export E:\\BCD.BAK<\/pre>\n<\/div>\n
\n
5] Format the EFI boot partition<\/h3>\n
Formatting the EFI boot partition is usually not<\/strong> required. However, if Windows Setup or the Windows Update process cannot service the boot files and causes the error 0x800F0922<\/code>, 0x80070002<\/code> (see this example<\/a>), etc., you may need to reformat the EFI partition and regenerate the BCD and boot files.<\/p>\n
To format the EFI partition (Volume 3 or Y: in this example), run:<\/p>\n
format y: \/fs:FAT32 \/q<\/pre>\n
Type the current<\/strong> volume label, as seen in the DiskPart output earlier. If the current volume label is empty, simply press Enter.<\/p>\n
\"format<\/p>\n
Click Y<\/strong> when prompted to proceed with the format.<\/p>\n
Type in the new<\/strong> volume label — e.g., EFI, ESP, etc.<\/p>\n
\n
6] Rebuild the BCD and Boot Files<\/h3>\n
Type the following command to regenerate the BCD<\/strong> and the boot files. The boot files will be sourced from the Windows directory.<\/p>\n
bcdboot E:\\Windows \/s Y: \/f UEFI<\/pre>\n
\"regenerate<\/p>\n
The output should show the message “Boot files successfully created.”.<\/p>\n
(Instead, if you see the error “Failure when attempting to copy boot files,” you’re probably typing the wrong drive-letter. Please recheck your Windows drive-letter by running bcdedit<\/strong>.)<\/em><\/p>\n
Note for dual-boot configurations<\/h4>\n
If you have a dual-boot or multi-boot Windows configuration (e.g., a parallel installation on another drive or partition), read below:<\/p>\n
For dual-boot or multi-boot Windows computer, additionally,<\/strong> run the following command to add those installations to the Boot Configuration Database.<\/p>\n
bootrec \/rebuildbcd<\/pre>\n
The above command scans all disks for Windows installations. You should see the “Successful Windows installations: #” message showing the list of Windows installations on the computer.<\/p>\n
If additional installations are detected, press “A<\/strong>” to add all the detected Windows installations into BCD.<\/p>\n
\"bootrec<\/p>\n
Here’s a sample output:<\/p>\n
Scanning all disks for Windows installations.\n\nPlease wait, since this may take a while...\n\nSuccessfully scanned Windows installations.\nTotal identified Windows installations: 1\n[1]  F:\\Windows\nAdd installation to boot list? Yes(Y)\/No(N)\/All(A):A<\/strong>\nThe operation completed successfully.<\/pre>\n
Note: <\/strong>If you ran the bcdboot<\/strong> command earlier, bootrec<\/strong> lists only the additional Windows installations, if any is present. If the BCD already includes a Windows installation entry, bootrec does NOT create a duplicate entry. And, if no additional<\/strong> instances are present, bootrec<\/strong> output shows “Total identified Windows installations: 0”<\/strong>.<\/div>\n
That’s it. The EFI partition, the boot files, and the BCD have now been rebuilt.<\/p>\n","protected":false},"excerpt":{"rendered":"
The EFI boot partition is a FAT32 partition that stores the boot files and the boot configuration data (BCD) to load Windows. Sometimes, the boot partition or the BCD may get corrupted, and the boot files remain unserviceable by the Windows Setup process. In that case, rebuilding the EFI partition and recreating the BCD & … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[8,869],"tags":[955,865,680],"class_list":["post-32027","post","type-post","status-publish","format-standard","hentry","category-windows-10","category-windows-11","tag-bcdedit","tag-diskpart","tag-windows-recovery-environment"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":80550,"url":"https:\/\/www.winhelponline.com\/blog\/backup-the-efi-system-partition\/","url_meta":{"origin":32027,"position":0},"title":"How to Backup the EFI System Partition","author":"Ramesh","date":"March 23, 2026","format":false,"excerpt":"The EFI partition contains the boot files and the boot configuration database (BCD). Some OEMs also store the BIOS image backups and additional tools in the EFI partition. This post explains how to back up the files in the EFI partition. Backup the EFI System Partition The EFI partition has\u2026","rel":"","context":"In "Windows 10"","block_context":{"text":"Windows 10","link":"https:\/\/www.winhelponline.com\/blog\/category\/microsoft\/windows\/windows-10\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":74860,"url":"https:\/\/www.winhelponline.com\/blog\/create-move-efi-partition-windows\/","url_meta":{"origin":32027,"position":1},"title":"How to Move EFI System Partition to Another Drive in Windows 10 or 11","author":"Ramesh","date":"April 18, 2024","format":false,"excerpt":"The EFI partition is created automatically when you install Windows. However, after adding a second HDD\/SSD and installing Windows on that disk, you may realize that the EFI system partition remains on the old hard disk. You wonder how to move the EFI partition from the old hard drive to\u2026","rel":"","context":"In "Windows 10"","block_context":{"text":"Windows 10","link":"https:\/\/www.winhelponline.com\/blog\/category\/microsoft\/windows\/windows-10\/"},"img":{"alt_text":"EFI boot partition on another disk","src":"https:\/\/i0.wp.com\/www.winhelponline.com\/blog\/wp-content\/uploads\/2024\/04\/move-efi-partition-os-drive.png?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.winhelponline.com\/blog\/wp-content\/uploads\/2024\/04\/move-efi-partition-os-drive.png?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.winhelponline.com\/blog\/wp-content\/uploads\/2024\/04\/move-efi-partition-os-drive.png?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/www.winhelponline.com\/blog\/wp-content\/uploads\/2024\/04\/move-efi-partition-os-drive.png?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":74926,"url":"https:\/\/www.winhelponline.com\/blog\/reagentc-exe-operation-failed-2\/","url_meta":{"origin":32027,"position":2},"title":"REAGENTC.EXE: Operation failed: Error 2 or Error 3bc3","author":"Ramesh","date":"April 24, 2024","format":false,"excerpt":"When you attempt to enable Windows RE by running the reagentc \/enable command, the following error may be shown: REAGENTC.EXE: Operation failed: 2 REAGENTC.EXE: An error has occurred. (or) REAGENTC.EXE: Operation failed: 3bc3 or REAGENTC.EXE: Unable to update Boot Configuration Data. The ReAgent.log may record the following error: Info [ReAgentc.exe]\u2026","rel":"","context":"In "Windows 10"","block_context":{"text":"Windows 10","link":"https:\/\/www.winhelponline.com\/blog\/category\/microsoft\/windows\/windows-10\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":75307,"url":"https:\/\/www.winhelponline.com\/blog\/bcdboot-failure-initializing-library-system-volume\/","url_meta":{"origin":32027,"position":3},"title":"Bcdboot “Failure when initializing library system volume”","author":"Ramesh","date":"May 28, 2024","format":false,"excerpt":"When you run the Bcdboot command to copy boot files to the EFI system partition, the following error may occur: Failure when initializing library system volume. The output contains the list of Bcdboot command-line arguments. 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