No executable found matching command dotnet-projectmodel-server

I had this same problem. I was able to fix it by uninstalling Microsoft .NET Core 1.0.1 - SDK Preview 3 (x64) and reinstalling the .NET Core 1.1 SDK from here:

https://www.microsoft.com/net/core#windowscmd

Another option to fix this is to add a Solution folder called "Solution Items" and add a global.json file in it with an "sdk" element specifying the correct SDK version if you have multiple installed side-by-side. I installed 2017 RC and I started getting this error because it installs Preview 4. I don't want to uninstall Preview 4 or 2017 will stop working. Adding the global.json file with the following text fixed it for me. (check your %PROGRAMFILES%\dotnet\sdk folder for installed SDK versions.)

{ "sdk" : { "version" : "1.0.0-preview2-1-003177" } }

Update (11 May, 2017)

According to the new Announcing .NET Core Tools 1.0 blog post:

We’re now encouraging everyone to migrate to MSBuild and csproj from project.json. As I stated above, we will not be supporting any of the new .NET Core tools in Visual Studio 2015. We also won’t be updating the Visual Studio 2015 project.json-based tools.

Original answer

There is a closed issue related to this problem in the .NET Core CLI repo:

Unable to start process "dotnet-projectmodel-server" while starting VS2015

According to the post Changes to Project.json, since Preview 3 the .NET Core tooling moved from .xproj/project.json to .csproj/MSBuild. So basically you have three choices:

1. Continue using the .xproj/project.json format with a Preview 2 SDK (as said in @Tim Schmidt's answer)

2. Use the dotnet migrate tool or the VS 2017 RC to migrate your existing project.json assets to csproj. Note that if you are using VS 2015, you will lost the .NET Core Tooling until the VS 2015 Tools (Preview 2) is updated.

3. Work with project.json and csproj on the same machine, switching between the Preview 2 and Preview 3+ with the help of the global.json file (as said in @randcd's answer).

But, if you plan to migrate to .csproj/MSBuild, pay attention to the post Using MSBuild to build .NET Core projects:

We recommend that most people targeting .NET Core with new projects today use the default tooling experience with project.json because of the following reasons:

• MSBuild doesn't yet support a lot of the benefits of project.json
• A lot of the ASP.NET based tooling doesn't currently work with MSBuild projects
• When we do release the .NET Core tooling that uses MSBuild, it will be able to automatically convert from project.json to MSBuild projects

I got this message when I was trying out a new Angular2 with .NET Core template from the ASP.NET Core Template Pack.

Basically, you'll need a global.json file as a Solution Item in the Solution folder (NOT Projects)

{
  "projects": [ "src", "test" ],
  "sdk": {
    "version": "1.0.0-preview2-003131"
  }
}

For more information, you can read further on this page.

Dot Net Core Tutorials

In my case, after installing .net core 1.1.0 there were still versions 1.0.1 installed. Delete old versions and reinstall Microsoft .NET Core tools.