Could not create an instance of startup object. ThisAddIn in assembly RepliconWS, Version=, Culture=neutral, PublicKeyToken=null. RRS feed

  • Question

  • Hi,

      I am trying to add a ribbonbar in Excel using VSTO. I am using VS2010 Office tools and Visual Studio version 2015 (also tried in 2017). After I publish and open excel I get this message below. I can click OK and continue and everything still works but this message is annoying and I need to share this solution with the entire company. 

    No results in google seems to converge on a solution except suggesting the dll version should be married to the lib version. I built this from scratch, so I assume it would have pulled in what ever version was needed. 

    Can anyone please suggest a fix or workaround. Any help is greatly appreciated.

    ************** Exception Text **************
    Microsoft.VisualStudio.Tools.Applications.Runtime.CannotCreateStartupObjectException: Could not create an instance of startup object RepliconWS.ThisAddIn in assembly RepliconWS, Version=, Culture=neutral, PublicKeyToken=null.
       at Microsoft.VisualStudio.Tools.Office.Runtime.DomainCreator.ExecuteCustomization.CreateEntryPoint(String entryPointTypeName)
       at Microsoft.VisualStudio.Tools.Office.Runtime.DomainCreator.ExecuteCustomization.Microsoft.VisualStudio.Tools.Office.Runtime.Interop.IExecuteCustomization2.LoadEntryPoints(IntPtr serviceProvider)

    ************** Loaded Assemblies **************

    Friday, December 8, 2017 5:20 PM

All replies

  • Hello sgopinath,

    I need confirm with you some information to reproduce your issue.

    What's the version of your Office?

    What application are you developing? Is a document-level document or application-level add-in?

    How do you publish the project? ClickOnce?

    Could you share a simply project so we could try to use it to reproduce your issue?

    You could share the project via Cloud Storage, such as One Drive, and the put link address here.

    By the way, you could try to refer to below thread to check if it is helpful.

    Could not create an instance of Start up object

    Best Regards,


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    Monday, December 11, 2017 5:05 AM