Error loading type library/DLL (Microsoft.Office.Interop.Excel.Application)

Ned picture Ned · Jan 1, 2013 · Viewed 12.2k times · Source

I'm trying to create an Excel document via C#. When I run the application, it gives the following error:

Unable to cast COM object of type 'System.__ComObject' to interface type 'Microsoft.Office.Interop.Excel.Application'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{000208D5-0000-0000-C000-000000000046}' failed due to the following error: Error loading type library/DLL. (Exception from HRESULT: 0x80029C4A (TYPE_E_CANTLOADLIBRARY)).

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It was working fine before I've upgraded Visual Studio from 2010 to 2012. I've also upgraded Office from 2010 to 2013.

  • There are no errors/warnings at output window.
  • Microsoft.Office.Interop.Excel reference is added

Answer

Ned picture Ned · Jan 2, 2013

I was struggling with this error for a few days . I've finally found the solution.

It occurs because I’ve installed Office 2013 instead of Office 2010 which I was using with old version of my project. After I upgraded my Office, the project was no longer able to link Excel reference.

Even though I referenced new Excel library which is 15.0, it didn't work.

What I did is that:

  • Delete the Excel reference (Microsoft.Office.Interop.Excel). Version 15.0, in my case.
  • Install Microsoft Excel (whichever version you had been using. Version 2010 for me)
  • Add the Excel reference (older one. Version 14.0, in my case)