I have a ASP.NET MVC 3 project, which uses DotNetOpenAuth, retrieved via NuGet. Package restore is enabled. The project uses .NET 4 (the full profile, not client).

In Visual Studio 2012, the project compiles and runs fine.

In Visual Studio 2013, I get the following error:

> 
> The type or namespace name 'DotNetOpenAuth' could not be found (are you missing a using directive or an assembly reference?)
> 
> 
> 

The DLLs are successfully restored to the `packages` folder, and are also correctly copied to the `bin` folder of the website project. All appropriate `using`s have been added. Each time I have tested a change from a clean working directory. All of the other projects in the solution compile fine. The assembly references look like this in the `Website.csproj` file:

```
<Reference Include="DotNetOpenAuth.Core, Version=4.3.0.0, Culture=neutral, PublicKeyToken=2780ccd10d57b246, processorArchitecture=MSIL">
  <HintPath>..\..\packages\DotNetOpenAuth.Core.4.3.1.13153\lib\net40-full\DotNetOpenAuth.Core.dll</HintPath>
</Reference>

```

How can I solve this?