VS 2015 fails to load any project after installing Update 3 RTM with .Net Core RRS feed

  • Question

  • Scenario:

    1. I have VS 2015 Enterpise with Update 3

    2. I can't install VS 2017 due to restrictions at work

    3. I wanted to run .Net Core from VS 2015

    4. I've installed Dotnet Core dotnet-1.1.1-sdk-win-x32.exe

    5. Still VS 2015 wasn't able to create .Net core Projects

    6. I've installed  DotNetCore.1.0.1-VS2015Tools.Preview2.0.3.exe

    After that VS 2015 as able to create new .Net Core Projects. However it fails to load any old project after this install.

    It's saying that : "global element Configuration has already been declared".

    but there is NO duplication in my Web.config.

    nor in my Machine.config

    I tried to remove VS 2015 completely. And resintalled it. Still getting the same error

    I tried to cleanup all VS 2015 foot print from my Machine using

    After the completely uninstall I've installed it again and applied NO update NO patch nothing.

    Still getting the same error in app.config or web.config: "global element Configuration has already been declared"

    Then when I click F5 and try to runt he solution IIS express returns me a message

    HTTP Error 500.19 - Internal Server Error

    The requested page cannot be accessed because the related configuration data for the page is invalid.

    More Information:

    This error occurs when there is a problem reading the configuration file for the Web server or Web application. In some cases, the event logs may contain more information about what caused this error.

    If you see the text "There is a duplicate 'system.web.extensions/scripting/scriptResourceHandler' section defined", this error is because you are running a .NET Framework 3.5-based application in .NET Framework 4. If you are running WebMatrix, to resolve this problem, go to the Settings node to set the .NET Framework version to ".NET 2". You can also remove the extra sections from the web.config file. 

    THERE is absolutely NO duplication in the web.config but still I'm getting this error message =/

    • Moved by 宝宝徐 Friday, June 9, 2017 6:35 AM
    Monday, May 22, 2017 4:00 PM

All replies

  • Hi Ricardo,

    Thank you for posting in MSDN forum.

    >>After that VS 2015 as able to create new .Net Core Projects.

    If it works fine on creating new project, it indicates that there is nothing wrong with your VS setup, the template is completely ok.

    >>However it fails to load any old project after this install.It's saying that : "global element Configuration has already been declared".

    According to the error message, from the Visual Studio documentation, please try with following steps:

    1. Open a file in the XML editor.

    2. In the document properties window, click the button on the Schemas field.

    The XML Schemas dialog box is displayed. The dialog box lists all schemas with an .xsd extension in the schema cache (including schemas referenced in the catalog.xml file), and also any schema that is in the current solution, open in Visual Studio, referenced in an xsd:schemaLocation attribute, or referenced in the Schemas property.

    3. Select the schemas to use for validation by doing one of the following:
       Select a schema listed in the XML Schemas dialog, click the Use column, and then select Use this schema. 
       Select multiple schemas listed in the XML Schemas dialog, right-click and select Use this schema.

    4. Click OK.

    In addition, this forum is talking about VS setup and installation, as your issue is much related to the .net core configuration file and Web application, I suggest you could post in forum for a much professional and dedicated support.

    Thank you for your understanding and cooperation.

    Best Regards,

    MSDN Community Support
    Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact

    • Proposed as answer by 宝宝徐 Wednesday, May 24, 2017 9:01 AM
    Tuesday, May 23, 2017 8:57 AM