When deploying an ASP.NET MVC 5 application, I wanted to deploy it on Windows Azure to test it. Thanks to Visual Studio, the deployment was really easy but, as soon as I tried to browse the website, I received the following error message:

Could not load file or assembly ‘Microsoft.Web.Infrastructure, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35′ or one of its dependencies. The system cannot find the file specified.

This is also one of a few component libraries that are needed for deploying an MVC application:

• System.Web.Helpers.dll (required by the web.config)
• System.Web.Mvc.dll
• System.Web.Razor.dll
• System.Web.WebPages.dll
• System.Web.WebPages.Razor.dll
• Microsoft.Web.Infrastructure.dll

The system libraries are installed with .NET 4, however, 'Microsoft.Web.Infrastructure.dll' is only installed when Visual Studio is installed on the machine.  Therefore, short of needing to install MVC and Visual Studio on a production environment, we need to deploy the libraries with out application - and we'd like to do so automatically.

As one possible fix, please try the following:
1. Run the following command in the Package Manager Console. (If you are using Visual Studio, this can be reached via menu options “Tools –> Library Package Manager –> Package Manager Console:)

PM> Install-Package Microsoft.Web.Infrastructure
You will see the following messages if it is successfully installed.
     Successfully installed 'Microsoft.Web.Infrastructure 1.0.0.0'.
   Successfully added 'Microsoft.Web.Infrastructure 1.0.0.0' to Web.

2. You will notice that Microsoft.Web.Infrastructure.dll has now been added as a Reference (can be seen in the references folder of your project in in Solution Explorer)
3. If you look at the properties of this reference you will notice that “Copy Local” has been set to “True” by default.
4. Now when you “Publish ” your project, Microsoft.Web.Infrastructure.dll will be deployed.