Windows 8 Pro cannot boot - Error 0xC000021a

Anonymous
2012-11-25T18:10:13+00:00

Hi

I upgraded my son's laptop from Windows 7 to Windows 8 Pro. I has been working fine for a few weeks. But now when booting It halts iwth the error code 0xc000021a. I have tried the following options

Refresh - this fails with the error 0xc000021a

System Restore - this fails with 0xc000021a

Safe mode boot does not work

I can start the cmd console

Any suggestions as to how to proceed?

Windows for home | Previous Windows versions | Performance and system failures

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  1. Anonymous
    2012-11-25T21:46:18+00:00

    I have run into the same problem on a Lenovo Ideapad u410, has a hybrid drive setup with an SSD for cache and a 500GB traditionall HDD. 

    When I try refresh it tells me: "The drive where Windows is installed is locked.  Unlock the drive and try again.

    Reset: "Unable to reset your PC.  A required drive partition is missing."

    Automatic repair does not fix anything.

    Anyone have any ideas as well?

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  2. Anonymous
    2012-11-26T13:28:50+00:00

    Hi,

    I have additionally looked at c:\windows\system32\Logfiles\Srt\SrtTrail.txt and see that the boot diagnostics pass successfully up to and including Internal state check. It states that the Root cause found is:

    Startup Repair has tried several times but still cannot determine the cause of the Problem.

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  4. Anonymous
    2012-12-17T10:37:04+00:00

    Just wondering if Arron's suggested fix worked.  The reason I ask is that his response is for a failure during the upgrade process from windows 7 to 8. Based on the information you provided, it sounds like you had your sons system up and running in windows 8 and some security update from ms was installed and after the usual reboot to complete the install, you got the 21a error. 

    Just wondering, it seems like maybe some people do not understand that an upgrade is different from an update.

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  5. Anonymous
    2012-12-22T19:57:02+00:00

    I have the same problem on my HP desktop that we upgraded a few weeks ago from windows 7 to windows 8. A windows update came through that morning, and it rebooted then, but later that day, it never came back. Same error the above posts noted. Cannot go to desktop, cannot go to safe mode, cannot boot from recovery cd either. No system recovery or reset works. I managed to copy my personal files to another hard drive and back up to another computer, but my $1500 HP is useless. How can I fix the Windows 8 Error 0xc000021a without booting to desktop, from the command line?

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