You are able to work with your application, but when you build and run the application, you notice the output window showing up with the little exclamation mark within a yellow triangle.
This error typically indicates one the following:
The Microsoft .NET Framework is not properly installed on your machine with sufficient access permissions.
There is no Web Server (such as Microsoft IIS) installed on your machine.
The order of installation of Microsoft IIS and the .NET Framework is not correct.
Step 1: Re-register the .NET Framework with Microsoft IIS to see if repairing the .NET Framework installation fixes the issue. In Iron Speed Designer, select Build, Re-register ASP.NET with IIS....
Step 2: If this does not fix the issue, download and re-install the Microsoft .NET Framework.
Step 3: Ensure that the Microsoft .NET Framework is installed after Microsoft IIS is installed. See Verifying the .NET Framework was Installed after Microsoft IIS for details.
Part VII: Troubleshooting Applications
Application Generation and Compilation Error Messages