Are office plugin projects forced to target .NET 3.5 in Visual Studio 2010? RRS feed

  • Question

  • I'm a developer supporting a plugin which targets Microsoft Word 2007. Older versions of this plugin were developed in Visual Studio 2005, and depended on the .NET Framework 2.0. After upgrading the plugin's solution file to be compatible with Visual Studio 2010, Visual Studio changed our plugin's target .NET environment 2.0 to 3.5. If I attempt to downgrade it back to 2.0, Visual Studio gives an error message indicating that "The .NET Framework version you selected is not supported by this project type." Is this deliberate? Does Visual Studio 2010 no longer support the .NET Framework 2.0 as a target environment for Office plugins? Or, is there a way to work around this limitation?

    Additionally, after reverting the solution file to an older version, and attempting to re-open the solution in Microsoft Visual Studio 2005, I receive an error, "The project type is not supported by this installation." The solution file can still be opened, but the Office plugin subproject doesn't open correctly. I'm confused because the solution file and project metadata did not change, but somehow the project is no longer able to be opened. It's possible this is because of some environmental change - for example, I needed to install new versions of the VSTOR libraries. But, it makes it more difficult to verify assumptions I'm making about the project configuration, when I can't open both projects side-by-side on the same machine.

    Thanks for your time.

    • Edited by piepera Wednesday, September 21, 2011 5:10 PM Formatting
    Tuesday, September 20, 2011 5:39 PM


  • Hi piepera,


    Thanks for posting in the MSDN Forum.


    It’s based on my experience that your issue isn’t based on whether Visual Studio supports.NET Framework 2.0. I assume that when you move your project form the Visual Studio 2005 (use VSTO 2005SE runtime, that only support .NET Framework 2.0) to Visual Studio 2010(use VSTO 4.0 need .NET Framework 3.5 SP1 or .NET Framework 4.0) so the Visual Studio show the particular error message to you. So your issue is based on Visual Studio 2005 and Visual Studio use different VSTO runtime and different VSTO runtime need different .NET Framework support.


    I hope what I said can solve your issue.


    There is a link for VSTO runtime and the support .NET Framework:


    Have a good day,



    Tom Xu [MSFT]
    MSDN Community Support | Feedback to us
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    Thursday, September 22, 2011 2:36 AM