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Boot Manager recover from critical error. Some essential variables are absent or corrupted and Boot Manager has restored them from default configuration. Press Esc to continue or F1 to enter Setup. RRS feed

  • Question

  • Hi there

    Getting a painful error when running a Windows 10 rebuild task sequence.

    Quick bit of background.

    We use a third-party content management tool which integrates with SCCM 2012 (we have have SP2). This tool basically caches task sequence and application/package content on the local disk, makes it available so peers who require software don't need to go to a DP. Our factory task sequence is built with a C: and D: drive. On the D: drive we store the cache folder for this tool, the idea being when we want to rebuild a machine we can do so from content on the local disk, and a bit of configuration in the task sequence. This worked perfectly when we built Windows 10 using legacy BIOS. Our rebuild task sequence flattened C: and then rebuilt C using content from D - all well and good. The only thing I had to add in was a run command task step to reset the mbr, with this command: Bootsect.exe /nt60 C: /mbr

    So that was fine. Then we changed to UEFI, for all the obvious benefits.

    Building a Windows 10 machine (using gpt disk) the first time is fine after UEFI is configured.

    But when I try to rebuild it (using a separate rebuild task sequence which only wipes C:) I am now seeing an error after the first reboot after the Windows 10 Apply Operating System task has run.

    Boot Manager recover from critical error. Some essential variables are absent or corrupted and Boot Manager has restored them from default configuration. Press Esc to continue or F1 to enter Setup.

    If I simply press Esc the task sequence continues and completes successfully. But obviously this a manual step I can't have in a task sequence.

    First thing I did was try to research this error. I'm guessing this might one of Microsofts top secret error messages because references to it are few and far between. Some see this error preceeded by this code - 0C00252 - but I don't see this. 

    No one has an answer or any in-depth information.

    I am guessing that Windows is restoring files from its binaries and updating or resetting Boot Manager in the EFI partition.

    Second thing I tried was a various fixes, including mapping v: to the EFI partition and then running:

    bcdboot C:\windows /s v: /f UEFI

    This made no difference. Tried running bcdboot, and a couple of bootrec commands, /fixboot and /rebuildbcd (I gathered the bootrec files from the recovery wim).

    No joy.

    My question is simply: what can I do to automate this repair? What can I do configure the task sequence/Windows to perform this fix automatically so it doesn't halt the task sequence?

    Regards

    John



    • Edited by Taw Jackson Wednesday, August 17, 2016 8:08 AM
    Tuesday, August 16, 2016 7:49 PM

Answers

  • Hi John,

    In a UEFI boot configuration, Windows boot loader and it's configuration will be stored inside a small hidden partition called EFI System Partition. UEFI BIOS in modern laptops will check and make sure the boot files are not corrupted or compromised before loading Windows. If the validation check failed, entire boot configuration and the boot manager will be restored from a backup copy.

    I am not sure how your boot loader became corrupted. There is multiple possibilities. For example, a stealth type malware like Rootkit's may try to modify the boot configuration. Trying to install Linux distros may also result in the same. Another possibility is an unexpected or improper shutdown which resulted in file corruption.

    There is a similar case that shows  the same error message, check it for assistance.

    https://github.com/rhinstaller/efibootmgr/issues/7

    Please Note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.

    Regards


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    Thursday, August 18, 2016 6:14 AM
    Moderator