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FIX: Missing root certificate prevents Keyman Desktop from installing correctly

NOTE: This archived documentation has not been updated recently and may contain information that is no longer relevant


When installing Keyman Desktop or Keyman Developer on Windows XP, you may receive errors such as:

  • "Addin Library C:\Program Files\Tavultesoft\Keyman Engine 7.0\Addins\RichEdit\RichEdit.kma failed to install/uninstall."
  • "DAX Error: Invalid Certificate"
  • "Unable to instantiate Keyman COM: Catastrophic failure, ClassID: {7D8879C6-D830-4796-8021-7B6FF69558E4}"

The installer then fails to successfully complete, or may complete but Keyman Desktop will fail to run with an error advising the file is corrupt.


Download and install the Root Update Package from Microsoft, from More information about this update is available in Microsoft KB article 931125.

This update from Microsoft does not show any messages to indicate it has completed. It will take only a few seconds to run.

After the update, reinstall Keyman Desktop.


Keyman Desktop validates the integrity of its files using a digital certificate which ensures that the program has not been modified. As Keyman Desktop operates in a trusted manner on your system, interepting every keystroke that you type, it is important that malware is prevented from piggybacking on the trust you give to Keyman Desktop. Digital certificates are an important part of this trust mechanism.

A digital certificate signature is validated by checking it against a root certificate, which is provided by Microsoft and installed with the operating system. Recent releases of Keyman Desktop are signed with a digital certificate that is based on a new root certificate, released since Windows XP Service Pack 3 was released. This means that the certificate cannot be validated because the root certificate cannot be found to verify it against.

Installing the root certificate update from Microsoft means that the certificate can be validated against the appropriate root certificate, and the install should then complete successfully.

Applies to:

  • Keyman Desktop Light 7.0
  • Keyman Desktop Professional 7.0
  • Keyman Developer Professional 7.0