How can I repair the Windows 8 EFI Bootloader?
Solution 1
I've spent a lot of time trying to get my Windows 8 PC to boot again after cloning to a new SSD and try to summarise how I finally got it all working -
Firstly, boot from a UEFI Windows 8 recovery disk (CD/DVD/USB) - I found that the automated recovery process didn't find the correct Windows partition, nor when I managed to add it to BCD settings would it make it reliably bootable e.g. using BCDEDIT I got it to find and launch the Windows partition but it refused to cold boot or would not "keep" the settings after a 2nd reboot or power off.
Go into the Advanced options and run the Command Prompt.
Enter diskpart
to use the DiskPart tool to ensure you have all the right partitions and to identify your EFI partition - the key thing here is that your EFI partition is formatted as FAT32:
DISKPART> sel disk 0
Disk 0 is now the selected disk.
DISKPART> list vol
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 E DVD-ROM 0 B No Media
Volume 1 C NTFS Partition 195 GB Healthy Boot
Volume 2 WINRE NTFS Partition 400 MB Healthy Hidden
Volume 3 FAT32 Partition 260 MB Healthy System
Then assign a drive letter to the EFI partition:
DISKPART> sel vol 3
Volume 3 is the selected volume.
DISKPART> assign letter=b:
DiskPart successfully assigned the drive letter or mount point.
Exit DiskPart tool by entering exit
and at the command prompt run the following:
cd /d b:\EFI\Microsoft\Boot\
bootrec /fixboot
Delete or rename the BCD file:
ren BCD BCD.bak
Use bcdboot.exe
to recreate BCD store:
bcdboot c:\Windows /l en-gb /s b: /f ALL
The /f ALL
parameter updates the BIOS settings including UEFI firmware/NVRAM, /l en-gb
is to localise for UK/GB locale. The localisation defaults to US English, or use en-US.
Reboot and cross your fingers.
This gave me headaches. I was going in circles for a long while. There isn't a lot of reliable info about fixing UEFI/Windows 8 at the time of writing.
[EDIT]
To re-enable Hyper-V, I also had to run the following from an Administrator Command Prompt within Windows after rebooting:
bcdedit /set {default} hypervisorlaunchtype Auto
bcdedit /set {default} nx OptIn
Solution 2
The other answers are helpful but this is what I had to do to fix mine.
I had a 1.5 TB hard drive with Windows 7 installed on it. I then installed Windows 8 onto a 150 GB SSD I bought. The 1.5 TB hard drive failed and I could hear it making a noise, my computer would no longer start, saying "please insert system disk". I thought that the bootloader was missing as it must have been on the 1.5 TB disk. It turns out it was but the problem then was the guides I followed would not rebuild the bootloader or whatever it is called as i did not have an EFI partition on the smaller 150 GB disk (this may have existed on the failed disk), it only had 1 partition which filled the entire disk.
I did not want to lose all my data so I entered the Command Prompt by booting from my Windows 8 install USB drive (noting that you cannot boot the UEFI version of this if that appears, select to boot from the just the USB drive without the UEFI appearing before it).
Once in Command Prompt (see the other answers for instructions) you need to shrink the partition. To do this, enter the following commands, pressing Enter after each one:
diskpart
list disk
select disk 0
list partition
select partition 1
shrink desired=200 minimum=200
create partition efi
list partition
select partition 2
format fs=fat32
These commands will create the EFI partition. Double-check everything by typing list vol
. You should see a 200 MB partition. You now need to assign it a letter. Do this by typing assign
,
then list vol
again to see what letter has been assigned.
Now this is done you need to copy the boot files to this newly created partition:
bcdboot C:\Windows /l en-gb /s B: /f ALL
Note: you must replace C:
with the drive letter of the partition that contains Windows, and B:
with the letter assigned to the EFI partition you just created.
I also entered the following commands:
bootrec /fix
bootrec /fixmbr
These both came back successful, no idea if they really did anything but who cares. Windows is now fully recovered.
Solution 3
Okay, I've had time to put together a proper outline here. It's long, but it's pretty complete and should help you see what's going on.
First, one way this can happen:
- Your BIOS loses its settings.
- No problem, all that stuff's stored in the EFI partition.
- ...except for the SATA IDE vs AHCI setting, for obvious reasons.
- Were you using SATA-AHCI? You're probably using SATA-IDE now.
- Did you try to boot before you figured that out?
- If you did, it failed. Did you let Windows try to fix it?
- If you did, BLAM, it may very well have destroyed the Boot Configuration Database.
- Make sure you're using the correct SATA setting you were using last time.
Here's what you've probably done by now. IF ANY OF THIS DOES NOT MATCH, CAREFULLY EVALUATE WHETHER THIS IS IN FACT YOUR PROBLEM, and READ this for ideas but don't FOLLOW it without thinking first.
- You have HOPEFULLY ignored all the crap about fixing the Master Boot Record (MBR), partition table, partition flags, and other garbage that DOES NOT APPLY to an EFI boot scenario. AT ALL. At best, you would be able to completely rebuild a new, unrelated, NON-EFI boot solution. That might not be trivial, however, because:
- You have figured out that Windows is certain it does not have a Boot Configuration Database, but it is, unfortunately, either completely clueless or VERY certain about where it goes-- you can't quite tell which.
- You're aware that the boot store is normally
(somewhere)\Boot\BCD
and that the file is HIDDEN; view it usingdir /a:hs
. - You've familiarized yourself a bit with
BCDedit.exe
and figured out that it will let you "mock up" a Boot Configuration Database in a staging file using/CreateStore
(and please don't name it "BCD"), that you can explicitly use the staging file with the/Store
option, that you can add a menu entry for the Windows Boot Manager using/Create {bootmgr}
, and that you SHOULD be able to import it using/Import
... - ...but when you try to do this, you can't. You look into the
/SysStore
option, which sounds right, but you can't get it to use another store because it's "ambiguous". You have a hunch that it knows where the store is-- or should be-- but you can't find it. - You've tried to use
MountVol
to mount the EFI partition, but it doesn't even show in the list, so you can't.
If ALL of that applies fairly closely to you, here is what MAY be going on:
- Windows can tell you're set up for EFI (you have booted the DVD via a UEFI boot, you have an EFI partition, etc.).
- It therefore knows WHERE TO LOOK for the BCD file-- however, it either somehow has the location wrong (not this problem, but similar) or the BCD has been deleted.
- Apparently, because it knows where it SHOULD be, this breaks
/SysStore
-- and actually, that's probably correct behavior, because otherwise you'd put it in the wrong place. - As near as I can tell,
MountVol
deliberately hides the EFI partition (or is somehow incapable of noticing it). This prevents mounting the filesystem, which prevents finding the correct subdirectory, verifying that the database exists, etc.
So here, finally, is what you need to do about it. The good news is that it's probably a lot simpler than you're hoping by now.
- You do indeed have to mount the EFI partition.
Actually, I have a hunch that's not strictly correct-- I strongly suspect the EFI partition is already mounted by some internal subsystem, which is whyBCDedit
gets cranky-- it doesn't see the database, but it knows where it should go. Whatever it does not have, however, is a drive letter. So-- what to do?
Well...how far back do your DOS roots go? Do you remember theAssign
command? Guess what. - Start
DiskPart
. - If you are not familiar with
DiskPart
, the way it basically works is a hierarchy of sets; you must select exactly one element at one level to proceed to the next. So,List Disk
, and thenSelect Disk n
wheren
is whatever's appropriate for you. - Use
List Partition
andList Volume
(note non-plural) to get some insight and identify your EFI partition.
It is usually a 100MB FAT32 partition markedSystem
. Keep in mind that your disk should be using a GPT partition table by now, so you may see quite a few partitions. Some of these are for emergency recovery-- fat lot of good they do for EFI problems, eh? Oh well.
Notice that the EFI partition, and a few others, do not have drive letters. If you're so inclined, you can also view the GPT partition attributes, which may give you a few tangentially-related "Aha" moments as well. Select Partition n
where n is the EFI partition. (I expect you could select the volume instead if you need to.)Assign
. That's it. Don't specify a drive letter; justAssign
.List Volume
. You should now see a drive letter assigned to the EFI partition.Exit
DiskPart.
And now... a big fat warning. You will probably go directly to S: (or whatever you got fromAssign
) and notice a Boot partition. "AHA!" You will say. "There is noBCD
file here!" First... remember that file is hidden. Second... dig around a bit more, and you will notice that while there isS:\EFI\Boot
and alsoS:\EFI\Microsoft\Boot
You need to check both of these for problems.S:\EFI\Boot
is for the motherboard, and contains the Windows Boot LOADER (and possibly other things for other operating systems). This has this name because the motherboard has no idea if you're going to have Windows or not, and needs a fixed path that makes sense.- Inspect
S:\EFI\Boot
. For Windows 7 Professional, 64-bit, you should see:bootx64.efi
If you have installed an EFI shell (always a good idea), you might additionally seeshellx64.efi
.
NOTE: Dual-boot Linux users usingchainloader+1
WILL NOT see an extra entry here. - Inspect
S:\EFI\Microsoft\Boot
using bothdir
anddir a:h
. For Windows 7 Professional, 64-bit, you should see a bunch of language templates (en_US
, etc.) and the following files:
...except that you probably don't seebootmgr.efi bootmgfw.efi memtest.efi BCD BCD.Backup.001 BCD.Backup.002
BCD
, do you? But those backup files sure look tempting. - Determine which backup file you want to use. Whatever recent changes it's missing are nowhere near as important as your ability to boot the system, so go for the one that's most intact. Probably you will see one large one and one fairly small one. The small one is already corrupt, and is an artifact of the failed repair process-- don't use it. If they're both large, use the older one. IN ANY CASE, make ADDITIONAL BACKUP COPIES OF THE BACKUPS somewhere else.
- Copy the backup you've decided to use to
BCD
. - Exit the shell, shutdown cleanly, and reboot.
- Tell Windows to start NORMALLY. At this point, it should start.
Q: What if you don't HAVE a backup BCD?
A: Well, that really shouldn't happen. It likely means you're either in the wrong directory, support EFI but weren't actually using it, or somehow rebuilt your entire EFI partition without all of the required Windows materials (possible, especially when using multiple versions of Windows). In that case, you'll need to copy the EFI materials from the DVD, then either modify or rebuild the Boot Configuration Database using BCDedit
.
Q: Can you give me an example of a scenario where BCDedit /SysStore
can be used to do anything at all on an EFI system?
A: So far, no.
Anyway, hope this helps solve some problems for people, or at least gets them thinking. As a very important final point, please note that you can mount and inspect your EFI partition under Windows normally using the DiskPart
: Assign
technique above. You should do this at least once, to get a complete backup of your EFI partition, BEFORE you run into this kind of trouble. I recommend one backup into a subdirectory on your C:
drive, and one on a USB flash drive.
Sorry that's so long-winded. I need to turn this into a proper article at some point, but there are so many people who are SO frustrated that I felt the need to document my experience as completely and rapidly as I could.
Solution 4
Windows 8 is still not out in final form, so problems are to be expected. You are in an area new to most of us, where the commands we used to use may not work anymore. To the commands listed by @soandos, I add this one that completely rebuilds the BCD :
bootrec /rebuildbcd
Try also to use the Advanced boot menu from Windows 8 and let us know what happens.
If nothing works, the article Repairing Windows 7 when they fail to boot has some advice on using bcdedit to correct boot errors. It would in any case be interesting to see what is the output of bcdedit on your computer.
[EDIT]
These links might contain some helpful ideas :
Recovering the Windows Bootloader from the DVD
Windows 7 Boot Manager Recovery Problem
Windows 7 Suddenly Won’t Boot – Repairing the Windows 7 Bootloader
Solution 5
The easiest way:
Follow the steps from the post above to locate BCD file and go to its directory.
If BCD file is hidden, type
attrib bcd -s -h -r
and press Enter. This will allow you to modify and overwrite the file.Type
ren bcd bcd.old
and press Enter. This renames the current BCD file.Type
Bootrec /RebuildBCD
and press Enter to force Windows 8 to rebuild the boot menu from scratch.Exit command prompt and shut down. Remove Windows Recovery Media and reboot. You're done!
Related videos on Youtube
![Elmo](https://i.stack.imgur.com/4rG9J.png?s=256&g=1)
Elmo
Updated on September 18, 2022Comments
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Elmo almost 2 years
I installed Windows 7 and Windows 8 in EFI mode on a hard disk some days ago. Today, the bootloader got missing/corrupted.
I currently have the Windows 8 installer on a flash drive and tried using the Automatic Repair option to repair the bootloader but it didn't do anything. The Startup Repair option is also missing in the Windows 8 installer.
How I can repair/recreate the EFI bootloader from the Command Prompt?
BCDEDIT
returns the following message:The requested system device cannot be found.
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Admin almost 12 yearsWhat is wrong with the current solutions?
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Admin almost 12 years@soandos I had the same problem. I executed the commands from you and harrymc, and everything works fine now! Many thanks to you both.
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Admin over 11 yearsJust as an FYI, but we've recently released an automated EFI repair tool for Windows 8: neosmart.net/blog/2013/…
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Admin over 10 yearsI did not expect people to be having so much trouble with UEFI windows 8... How does the system partition just vanish or get corrupt anyway? It's not even mounted in windows normally so filesystem corruption can't be it. And all current OSes are bug-free enough not to muck up an existing windows installation. In fact, even windows doesn't muck up linux on UEFI, surprise of surprises.
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Admin about 9 yearsThis doesn't apply if you're using Dynamic disks
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Elmo almost 12 yearsThis tool is only for boot.ini which is for Windows XP and older oses.
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harrymc almost 12 yearsI have added some links that could be helpful, although pertaining to Windows 7.
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soandos over 11 yearsDownvoter care to comment?
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Yuhong Bao about 11 yearsActually, MOUNTVOL does let you mount the ESP. You use MOUNTVOL letter: /S.
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Ramhound over 9 yearsThe
bootrec /fixmbr
command does not apply to the author's problem or situation. -
rainabba almost 9 yearsi: is my EFI partition (first on the disk), but it's empty. When I run
bcdboot c:\windows /s i: /f ALL
I get "BFSVC Error: Failed to set emement application device. Status = [c00000bb]" I've been fighting this battle for months and with each attempt, keep ending up with a flash drive that seems to contain my EFI boot files because I I can boot off of it, but if I remove it, I cannot boot. -
rainabba almost 9 yearsSo when you mount that EFI partition and don't find anything at all, how to proceed? I was thinking that
bcdboot c:/windows /s i: /f ALL
or such would get me started, but that just gets me "BFSVC Error: Failed to set element application device. Status = [c00000bb]" -
rainabba almost 9 yearsDespite seeing that error ever single time, it now appears that I have the EFI folder on that drive where I did not before. Still can't do much else without errors and can't boot, but that's something at least.
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rainabba almost 9 yearsDecided to try another route entirely. I plugged in another flash drive, wiped it, give it a drive letter then repeated using it as the target instead of my EFI partition. In short, I'm not booted into my Windows install, but off of that flash drive. I was NOT able to get booted off my EFI partition despite it having the files, it being the first partition (EFI, fat32, has the files) on my first drive.On the upside, this is an interesting way to keep someone out of my system. I just take this "key" out of my system and it won't boot.
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Mahmoud Al-Qudsi almost 9 yearsThis does not pertain to EFI bootloaders.
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zacharydl almost 8 yearsHeads up: this answer appears to be an MBR disk. On a GPT disk, diskpart.exe returns this message when marking a volume active: "The ACTIVE command can only be used on fixed MBR disks."
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Sahil about 7 yearsThanks a lot! This saved my day. I tried virtually everything out there and nothing worked. The step I was missing was the formatting the EFI volume. Once formatted the EFI volume. bcd boot command worked successfully and I have my windows 10 back up and running again.
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Abbafei about 7 yearsDid this from a windows 10 download ISO. didn't work at first, but ran the startup repair in the GUI menu afterwards and that did it, thank G-d. :-) I appreciate the help :-)
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Dusan Bosnjak 'pailhead' almost 7 yearsthis recipe felt the most promising but i hit
BFSVC Error: Could not open the BCD template store. STatus = [c000000f ]
:( -
ptetteh227 about 6 years+1 for telling me to choose the windows drive letter instead of the usual C:
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Jerzy Drożdż over 4 years+1 - Remember the most important sentnce Note: you must replace C: with the drive letter of the partition that contains Windows, and B: with the letter assigned to the EFI partition you just created. I fight with that by 13hours! Thanks man you save me next 12 hours :)
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Scott Petrack over 3 yearsJust a small tip about diskpart: all diskpart tokens -- both verbs and nouns -- are uniquely distinguished by their FIRST THREE LETTERS. In plain English: you can type (say) "lis par" for "list partition" etc