VS 2017 Error - Unable to start program http://localhost An operation is not legal

Scenario
You are trying to debug a web site in Visual Studio 2017

Error
Microsoft visual studio is giving the error: Unable to start program http://localhost An operation is not legal

Solution
Disable the JavaScript debugging

• On VS go to Tools >> Options
• Go to Debugging >> General
• Uncheck the option Enable JavaScript debugging for ASP.NET (Chrome and IE)
• Click OK and try again

VS 2017 MVC Core 2.0 error - Cannot find reference assembly 'Microsoft.AspNetCore.Mvc.Razor.ViewCompilation-x86.exe' file for package Microsoft.AspNetCore.Mvc.Razor.ViewCompilation-x86

Scenario

After compiling a MVC Core 2.0 project in VS 2017, the browser isn't displaying the site

Error
An unhandled exception occurred while processing the request.

Cannot find reference assembly 'Microsoft.AspNetCore.Mvc.Razor.ViewCompilation-x86.exe' file for package Microsoft.AspNetCore.Mvc.Razor.ViewCompilation-x86

Solution
Open the .csproj file in a text editor
In the section set the MvcRazorCompileOnPublish tag as true:
      <mvcrazorcompileonpublish>true</mvcrazorcompileonpublish>

VS 2017 MVC Core 2.0 publish fails

Scenario
Publish a MVC Core 2.0 project in Visual Studio 2017

Error
Severity
Error
Code
The command ""bin\Release\net461\Microsoft.AspNetCore.Mvc.Razor.ViewCompilation-x86.exe"
Description
@"obj\Release\net461\microsoft.aspnetcore.mvc.razor.viewcompilation.rsp"" exited with code 1

Solution
Open the .csproj file in a text editor
In the section set the MvcRazorCompileOnPublish tag as false:
      <mvcrazorcompileonpublish>false</mvcrazorcompileonpublish>

MVC Core - Duplicate Content Error after Upgrading Visual Studio 2017

Error

• Dotnet-aspnet-codegenerator-design has stopped working
• Duplicate 'Content' items were included. The .NET SDK includes 'Content' items from your project directory by default.
• Failed to build the project. Please fix the build errors and retry again

Reason

The problem is a change on the RC3 release of Visual Studio 2017, if you have globs in your project and you try to build it using the newest SDK, you'll get the error. Basically your content, such as the files in wwwroot are now getting imported by the default includes that are built-in to Visual Studio and by the manual rules in your csproj file.

Solution 1

Open your web project file .csproj and remove the duplicated items specified in the error message

Basically remove the ItemGroup tag with all the wwwroot paths.

Solution 2

Open your web project file .csproj

Look for the tag

Add the next tag false