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You may receive error message 0xC004D302 when windows activation problem, invalid product key  ..., this page contains some useful information to repair your computer error code 0xC004D302, if you fixed this error from this help article, you can email us (windowsxpregistrycleaner@gmail.com ) give your feedback, and we hope you can share this page to your friends if they need like you, thanks.


Windows 7 - activate error code 0xC004D302

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On already activated KMS Host a Windows Activation window comes up with the error, an error has occurred:

  • "Code: 0xC004D302
    Description: The Security processor reported that the trusted data store was rearmed."


  • Changes in the default permissions of the "C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys"
  • Corruption in the Licensing Files
  • If you have run the slmgr.vbs /rearm command and try to run any other activation command(/dlv or /dli for example) prior to rebooting you will experience this error. You must reboot after using the slmgr.vbs /rearm command prior to attempting activation.

How to repair?

To resolve this issue, if you continue to encounter this error after restarting the computer, proceed with the following:

  • Option 1:

    1. Launch a cmd window with administrative privs (i.e. using run as administrator).

    2. In this cmd window, run the following command:
    cacls %systemdrive%\ProgramData\Microsoft\Crypto\RSA\MachineKeys

    3. Collect output of this command

    Review the output. These ACLS (pasted below for reference) of this folder on the machine are wrong!


    The actual ACLs (you can try this on any Vista machine) should be -
    C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys Everyone:(special access:)


    This explains the activation failure. Now we need to find out the culprit changing ACLs on this folder.

    Vista activation (SLSvc.exe) uses MSDN documented Win32 CAPI (Cryptography API) to perform some cryptographic operations. SLSvc.exe runs as network-service and CAPI calls by SLSvc.exe fail if the ACLs on this folder change from the default values. If the ACLs on this folder change, then the same CAPI call from any application (not running as local-system or administrator) will fail. The current ACLs on this machine only provide read-access to non-admins (including NetworkService account) and therefore CAPI calls from SLSvc are failing.

    The easiest way to restore the right ACL would be to use cacls.exe to set it.

    The command for that would be:
    cacls %systemdrive%\ProgramData\Microsoft\Crypto\RSA\MachineKeys /S:"D:PAI(A;;0x12019f;;;WD)(A;;FA;;;BA)"

    Although it may appear so at first glance, this problem isn't limited to a specific hardware platform. This is because these older systems do not contain the ACPI_SLIC licensing table in the BIOS. The newer machines that have this table must go through the cryptographic checks (and thus they use the MachineKeys folder when doing so). Most OEMs started incorporating the ACPI_SLIC table in mid to late 2006.

    ACL changes are not logged in event viewer. If there's not a suspect already, the customer can audit object access after changing the MachineKeys folder to reflect the correct permissions to see what changes these permissions. (Check the More Information Section for steps to enable Auditing on "C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys folder")

  • Option 2:

    1. Launch a command prompt window with administrative privs (i.e. using run as administrator).

    2. Now Run the following command at the command prompt, (one after the other)

    slmgr -upk //(uninstalls product key)
    slmgr -rilc //(reinstalls licence files)
    slmgr -ipk <put the apropriate KMS Host Key>
    slmgr -ato //(activates the machine)

    This will now activate the KMS host and is ready to activate the KMS Clients.

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Microsoft help links for error 0xC004D302

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PC repair tool to fix this error

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  • If you still haven't fixed the windows 0xC004D302 error code:

    1. Please try the tool windows registry optimizer, it safely cleans PC errors & invalid entries cause slow speed, blue screen, deadlock errors and crashing, and repair registry problems to speedup your computer performances. It is easy to use and supports 25 languages. And you can read our review about this software first.

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Read our site other related articles...

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That is we find the informations to fix 0xC004D302 error in windows 7, hope our page is helpful to you, if you still need more guide detail, please contact the microsoft support for further help. 

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Activation Error 0xC004D302

Home > Categories > Windows 7 Error - Update: December 6, 2009
>>> Fix Windows Activation Error 0xC004D302

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