Security Update KB4512506 leads to BootBCD error

Hey Steve

I had the same problem today. Since I had a win 7 sys backup made with Macrium Reflect. I restored my system from the back up. During the restoration it displayed the target disc ..... my C: drive and showed that the boot manager partition had actually been removed fro the drive. Hopefully they will figure this out before support for Win 7 ends. I am in the process of building a new Win 10 Pro Rig so for now I am operating the same way you are.
JD

I had 3 Windows 7 UEFI boot 64bit computers affected by this patch yesterday. Here is the fix that I discovered that has worked for me. If the system boots to the automatic repair console, you can perform the fix from there, otherwise, you need to boot to an installation disc and run it from the recovery console. For my fix, I replace the winload.efi, winload.exe, winresume.efi and winresume.exe from a June copy that I found in a subfolder of the \windows\winsxs directory.

From the recovery console, determine the drive letter of your windows install (usually C) and change to it, it isn't necessarily the same as when windows is running - c:

cd \windows\winsxs
dir winload.efi /a /s

It will find a bunch, but for me, the most recent one is actually at the end of the directory listing. Find the one with a date in June, mine was from June 12, 2019..

cd c:\windows\winsxs\C:\windows\winsxs\amd64_microsoft-windows-b..vironment-os-loader_31bf3856ad364e35_6.1.7601.24499_none_b984965a9ca0bb23
(No line break in the above command.  You might find it useful to just type "notepad" in the command prompt so you can select the path from the CMD prompt and paste it into notepad, clean it up, remove the line break, add the "cd " to the front, and then paste it back into the command prompt.)

Once you are in the folder you found, if you type dir you will see the 4 files.

md c:\w (replace C with the drive letter of windows install
copy . c:\w
(should say 4 files copied)

cd \windows\system32
ren win*.efi *.xxx
ren winload.exe *.x
ren winresume.exe *.x
copy c:\w\*.*

exit

You can then restart the computer and it should boot, finish the updates, and then allow you to log in. I tried checking for updates and it did not find any more so I don't fear that it will try to reapply the patch. I have seen no side effect to running with this version of the files. I replaced all 4 just to be consistent even though you might have been able to just replace 1 or 2.

Furthermore, other steps I tried that were determined unnecessary was to use DISKPART to assign a drive letter to the hidden system volume, and rename the BCD file in c:\efi\microsoft\boot and then rebuild the BCD with bootrec /rebuildbcd command. I did these steps on the first 2 because I had messed up the BCD trying to fix it, but on my 3rd computer I had not messed with and went straight to the steps I listed above and they worked on the first try. Hope this helps.

-Brad

Thanks for your kind help.

Why is not Microsoft offering INMEDIATE solution to this issue?

Thanks, Brad, for your troubleshooting, it works for me.

like IT_Nuubo, I think Microsoft would be to retire the KB and publish the solution inmediately

Kind regards,

Exactly the same problem arose in our company with at least 7 computers. After applying updates (KB4512506, KB4474419, KB890830), computers no longer start (BootBcd error). If to do System Restore or Recovery, computer starts up again, but after trying to install the above updates again, the same error occurs. I have some fixes of how to restore PC from BCD error, but it is not normal that i have to do these fixes on many pc-s everyday.

I missed this message when it was posted, but in case someone else stumbles across this -

Most of my clients that were affected by this, the System Restore failed to fix.  I only had 1 computer where the System Restore would successfully revert back only to make the computer try to reinstall the update a day later.

Installing the "Optional" update KB3133977 prior to attempting to reinstall the updates resolved the issue and then the updates will install as expected.  Microsoft forgot to re-clasify KB3133977 as "important" to ensure it got installed first, which is why we all got stuck in the predicament.

-Brad

Same issue happend for me ...few servers ..patches  KB4512506  got failed , if we tried with dependecy patches it got installed after reboot ...not able to boot...is any solution there or any kbs came....plss help me out ....

The steps I outlined will resolve the issue.  If you do not have backup copies of the files (winload.efi and winload.exe), you will need to copy them from another server that is fully patched that didn't have this issue.

-Brad

UPDATE:

After doing Brads fix once more, I used the command bcdedit /set safeboot minimal in order to get the machine up in safe mode. It started and did nothing for the next 10 minutes. I went and did something else for the next 10 minutes, and when I got back it had started in normal mode. Don't know what happened, but it worked.