Visual Studio 2017 install breaks Visual Studio 2015 ASP.NET Core Projects

Question

After installing Visual Studio 2017 Professional I can't build my ASP.NET Core in Visual Studio 2015 Professional anymore. I never opened this project in VS2017

I get

The following error occured attempting to run the project model server process (1.0.0-preview3-004056).

Unable to start the process. No executable found matching command dotnet-projectmodel-server

I then created a brand new ASP.NET Core project in Visual Studio 2015 and I get the exact same message when loading my project.

Additionally when I want to build the project I get

MSB1009: Project File does not exist.

The same problem does not occur with ASP.NET 5 projects so It's only limited to ASP.NET Core

Visual Studio 2017 7 March Update

Ifa global.json is added like in the answers below get an error message for any .net framework version used in the global.json and that exist in the C:\Program Files\dotnet\sdk\ folder

Error MSB4019 The imported project "C:\Program Files\dotnet\sdk\X.X.X\Microsoft\VisualStudio\v14.0\DotNet\Microsoft.DotNet.Props" was not found. Confirm that the path in the declaration is correct, and that the file exists on disk.

Also when closing Visual Studio and reopening it again I get the original error message

Visual Studio 2017 updated the .NET Core SDK, which brought in quite a few changes, such as the move away from project.json and a number of optimizations towards the performance while working in Visual Studio. This is a breaking change in .NET core itself. — jessehouwing
I also installed VS 2017 RC on my machine that has VS 2015 update 3 and got the exact same error when trying to open an existing ASP.NET Core 1.0 app in VS 2015. This project opened just fine in VS 2015 before installing VS 2017 RC and I never tried opening it with VS 2017 RC. I uninstalled VS 2017 RC and the ASP.NET Core 1.0 app in opens just fine and builds now with VS 2015. So, apparently, contrary to what Microsoft says, you can't install VS 2017 RC on a machine that has VS 2015 on it. At least if you want to open ASP.NET Core 1.0 apps created with VS 2015 in VS 2015. — Stephen Peterson
Publishing is also broken with the default VS2017 ASP.NET Core RC template so I would advise to stay away until the RTM — dfmetro
Possible duplicate of No executable found matching command dotnet-projectmodel-server — Rosberg Linhares
I found a workaround for your March 7th update with the missing Microsoft.DotNet.Props. Go to your C:\Program Files\dotnet\sdk folder and find the folder that was installed just before 1.0.0 (in my case 1.0.0-preview2-1-003177). Replace sdk/version with that value in your global.json. Then dotnet restore — AngryHacker

Stephen Peterson Stephen Peterson · Accepted Answer · 2016-11-19T15:08:47

@ClaudioNunes and @MegaTron have the correct answer. After reading that answer, I realized my .NET Core solution did not have a global.json file. I added a new solution folder and added a global.json file. Since none of my projects are nested in sub folders, I only had to remove "src" and "test" from the projects array:

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

The project now opens correctly in VS 2015 with VS 2017 RC installed.

Visual Studio 2017 install breaks Visual Studio 2015 ASP.NET Core Projects

5 Answers