Your project is not referencing the ".NETFramework,Version=v4.5" framework.

I am using VS 2015.

Your project is not referencing the ".NETFramework,Version=4.5" framework. Add a reference to ".NETFramework,Version=4.5" in the "frameworks" section of your project.json, and then re-run NuGet restore.

I am getting this error on my Data Access and Business Logic layers, shortly after adding to my MVC Layer. Things were building fine until then, but I don't know what triggered this error. Here is my project.json:

{
  "version": "1.0.0-*",
  "description": "foo bar Class Library",
  "authors": [ "foo bar" ],
  "tags": [ "" ],
  "projectUrl": "",
  "licenseUrl": "",

  "frameworks": {
    "net451": { },
    "dotnet5.4": {
      "dependencies": {
        "Microsoft.CSharp": "4.0.1-beta-23516",
        "System.Collections": "4.0.11-beta-23516",
        "System.Linq": "4.0.1-beta-23516",
        "System.Runtime": "4.0.21-beta-23516",
        "System.Threading": "4.0.11-beta-23516"
      }
    }
  }
}

Here's what I have tried:

1. Replacing "dotnet5.4" with "net451" (and deleting it) as found in this answer.

Result is the same error.

2. Replacing "dotnet5.4" with "net45" and leaving the "net451". This results in a new error:

Your project.json doesn't have a runtimes section. You should add '"runtimes": { "win":{} }' to your project.json and then re-run NuGet restore.

I tried doing as this error suggested and adding

"runtimes": {
    "win":  {}
  },

This got me this error, which I can't seem to move past:

Your project.json doesn't list 'win' as a targeted runtime. You should add '"win": {}' inside your "runtimes" section in your project.json, and then re-run NuGet restore.

I've already added "win", and this is beginning to feel like a red herring. What am I doing altering the project.json directly, isn't NuGet handling this?