Interface not registered (Exception from HRESULT: 0x80040155) when calling Microsoft.Office.Interop.Outlook.MAPIFolder.get_Folders() RRS feed

  • Question

  • Hi All,

    I have an Outlook COM addin written in C#. It is working without any issues on most client machines, but since of late it has started giving the above Exception for some clients running Outlook 2010.

    I understand that the issue is that the particular interface is not registered properly on those machines. I would like to know what in dll that interface is located and what could cause it to be missing? Can it be a component that had been deselected during the installation of Outlook? If so, what is that component? Or should the dll be manually registered (using REGSVR32)? Or will running a simple repair on Outlook work?


    Tuesday, April 14, 2015 1:13 AM


  • Hello Thimila,

    What code do you use exactly?

    Try to run the problematic piece of code from VBA as a macro. Do you get the same error message? If so, you need to repair Outlook, it looks like windows registry entries were corrupted. 

    If you don't get such error in VBA it indicates that you didn't install/copy one of the required prerequisites to the end user PC (interop libraries, .net runtime and etc.). Make sure that all the required prerequisites are installed correctly. See Deploying an Office Solution for more information.

    Tuesday, April 14, 2015 6:13 AM