Mismatch office interop library (Library not registered) RRS feed

  • Question

  • Hi,

    I am developing .net Addin for outlook using VSTO,

    I deployed the plugin in a lot of stations, and i encountered this errors in a lot of them:

    System.Runtime.InteropServices.COMException (0x8002801D): Library not registered. (Exception from HRESULT: 0x8002801D (TYPE_E_LIBNOTREGISTERED))
       at Microsoft.Office.Interop.Outlook.ApplicationClass.get_LanguageSettings()

    Unable to cast COM object of type 'Microsoft.Office.Interop.Outlook.ApplicationClass' to interface type 'Microsoft.Office.Interop.Outlook._Application'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{00063001-0000-0000-C000-000000000046}' failed due to the following error: The media is write protected. (Exception from HRESULT: 0x80070013).
       at System.StubHelpers.StubHelpers.GetCOMIPFromRCW(Object objSrc, IntPtr pCPCMD, IntPtr& ppTarget, Boolean& pfNeedsRelease)
       at Microsoft.Office.Interop.Outlook.ApplicationClass.ActiveWindow()

    I searched a lot of time for a solution but the best one i found is to fix the typelib registry keys and repair office installation.

    (Described in here:

    I cannot offer this as a solution to the end users, is there a better solution for this problem?

    • Edited by sharon8811 Wednesday, October 25, 2017 11:11 AM typo
    Wednesday, October 25, 2017 11:10 AM

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