Both Entity Framework Core and Entity Framework 6 are installed

Question

I use Visual Studio 2017 and create a new ASP.NET Core project. I add migration for Entity Framework Core as below

add-migration "Initial Create"

and get the following error:

Both Entity Framework Core and Entity Framework 6 are installed. The Entity Framework Core tools are running. Use 'EntityFramework\Add-Migration' for Entity Framework 6.
Build Failed.

Do you know how to resolve this error?

---

UPDATE 1 - March 14, 2017 - Result received after running command

PM> dotnet ef migrations add "Initial Create"

I see the following output with error message at the end.

Welcome to .NET Core!
---------------------
Learn more about .NET Core @ https://aka.ms/dotnet-docs. Use dotnet --help to see available commands or go to https://aka.ms/dotnet-cli-docs.

Telemetry
--------------
The .NET Core tools collect usage data in order to improve your experience. The data is anonymous and does not include command-line arguments. The
 data is collected by Microsoft and shared with the community.
You can opt out of telemetry by setting a DOTNET_CLI_TELEMETRY_OPTOUT environment variable to 1 using your favorite shell.
You can read more about .NET Core tools telemetry @ https://aka.ms/dotnet-cli-telemetry.

Configuring...
-------------------
A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up
 to a minute to complete and will only happen once.
Decompressing 0%Decompressing 1%Decompressing 2%Decompressing 3%Decompressing 4%
Decompressing 5%Decompressing 6%Decompressing 7%Decompressing 8%Deco
mpressing 9%Decompressing 10%Decompressing 11%Decompressing 12%Decompressing 13
%Decompressing 14%Decompressing 15%Decompressing 16%Decompressing 17%
Decompressing 18%Decompressing 19%Decompressing 20%Decompressing 21%De
compressing 22%Decompressing 23%Decompressing 24%Decompressing 25%Decompressin
g 26%Decompressing 27%Decompressing 28%Decompressing 29%Decompressing 30%
Decompressing 31%Decompressing 32%Decompressing 33%Decompressing 34%
Decompressing 35%Decompressing 36%Decompressing 37%Decompressing 38%Decompre
ssing 39%Decompressing 40%Decompressing 41%Decompressing 42%Decompressing 43%
Decompressing 44%Decompressing 45%Decompressing 46%Decompressing 47%
Decompressing 48%Decompressing 49%Decompressing 50%Decompressing 51%Deco
mpressing 52%Decompressing 53%Decompressing 54%Decompressing 55%Decompressing 
56%Decompressing 57%Decompressing 58%Decompressing 59%Decompressing 60%
Decompressing 61%Decompressing 62%Decompressing 63%Decompressing 64%
Decompressing 65%Decompressing 66%Decompressing 67%Decompressing 68%Decompress
ing 69%Decompressing 70%Decompressing 71%Decompressing 72%Decompressing 73%
Decompressing 74%Decompressing 75%Decompressing 76%Decompressing 77%
Decompressing 78%Decompressing 79%Decompressing 80%Decompressing 81%Decomp
ressing 82%Decompressing 83%Decompressing 84%Decompressing 85%Decompressing 86
%Decompressing 87%Decompressing 88%Decompressing 89%Decompressing 90%
Decompressing 91%Decompressing 92%Decompressing 93%Decompressing 94%De
compressing 95%Decompressing 96%Decompressing 97%Decompressing 98%Decompressin
g 99%Decompressing 100% 5083 ms
Expanding 0%Expanding 1%Expanding 2%Expanding 3%Expanding 4%Expanding 5%Ex
panding 6%Expanding 7%Expanding 8%Expanding 9%Expanding 10%Expanding 11%
Expanding 12%Expanding 13%Expanding 14%Expanding 15%Expanding 16%Expanding 17%
Expanding 18%Expanding 19%Expanding 20%Expanding 21%Expanding 22%Expand
ing 23%Expanding 24%Expanding 25%Expanding 26%Expanding 27%Expanding 28%
Expanding 29%Expanding 30%Expanding 31%Expanding 32%Expanding 33%Expanding 34
%Expanding 35%Expanding 36%Expanding 37%Expanding 38%Expanding 39%Ex
panding 40%Expanding 41%Expanding 42%Expanding 43%Expanding 44%Expanding 45%
Expanding 46%Expanding 47%Expanding 48%Expanding 49%Expanding 50%Expandin
g 51%Expanding 52%Expanding 53%Expanding 54%Expanding 55%Expanding 56%
Expanding 57%Expanding 58%Expanding 59%Expanding 60%Expanding 61%Expanding 62%
Expanding 63%Expanding 64%Expanding 65%Expanding 66%Expanding 67%Expa
nding 68%Expanding 69%Expanding 70%Expanding 71%Expanding 72%Expanding 73%
Expanding 74%Expanding 75%Expanding 76%Expanding 77%Expanding 78%Expanding 
79%Expanding 80%Expanding 81%Expanding 82%Expanding 83%Expanding 84%
Expanding 85%Expanding 86%Expanding 87%Expanding 88%Expanding 89%Expanding 90%
Expanding 91%Expanding 92%Expanding 93%Expanding 94%Expanding 95%Expand
ing 96%Expanding 97%Expanding 98%Expanding 99%Expanding 100% 13884 ms


dotnet : No executable found matching command "dotnet-ef"
At line:1 char:1
+ dotnet ef migrations add "Initial Create"
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (No executable f...and "dotnet-ef":String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError

---

UPDATE 2 - March 14, 2017 - Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Configuration;
using OdeToFood.Services;
using OdeToFood.Entities;
using Microsoft.AspNetCore.Routing;
using Microsoft.AspNetCore.StaticFiles;
using Microsoft.AspNetCore.Identity.EntityFrameworkCore;

namespace OdeToFood
{
    public class Startup
    {
        public IConfiguration Configuration { get; set; }

        public Startup(IHostingEnvironment env)
        {
            // TN - Read setting files
            var builder = new ConfigurationBuilder()
                            .SetBasePath(env.ContentRootPath)
                            .AddJsonFile("appsettings.json")
                            .AddEnvironmentVariables();

            Configuration = builder.Build();
        }

        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();
            services.AddSingleton(Configuration);
            services.AddSingleton<IGreeter, Greeter>();
            services.AddScoped<IRestaurantData, SqlRestaurantData>(); // TN - One instance of this service for each HTTP request.
            services.AddDbContext<OdeToFoodDbContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
            services.AddIdentity<User, IdentityRole>()
                .AddEntityFrameworkStores<OdeToFoodDbContext>();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            loggerFactory.AddConsole();

            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                //app.UseExceptionHandler("/error");
                //app.UseExceptionHandler(new ExceptionHandlerOptions { ExceptionHandlingPath="/error" });

                app.UseExceptionHandler(new ExceptionHandlerOptions
                {
                    ExceptionHandler = context => context.Response.WriteAsync("Opps!")
                });
            }

            //app.UseDefaultFiles();// TN - will pick index.html
            //app.UseStaticFiles();

            app.UseFileServer(); // TN - This will include UseDefaultFiles() and UseStaticFiles

            /*
            app.UseWelcomePage(new WelcomePageOptions
            {
                Path = "/welcome"
            });

            app.Run(async (context) =>
            {
                // TN - Read directly from configuration file
                //var message = Configuration["Greeting"];

                // TN - Dependency Injection - Read from configuration string via IOC
                var message = greeter.GetGreeting();
                await context.Response.WriteAsync(message);
            });
            */


            app.UseIdentity();

            //app.UseMvcWithDefaultRoute();
            app.UseMvc(ConfigureRoutes);

            // TN - if no route matches
            app.Run(ctx => ctx.Response.WriteAsync("Not found."));
        }

        private void ConfigureRoutes(IRouteBuilder routeBuilder)
        {
            //Home/Index
            routeBuilder.MapRoute("Default",
                "{controller=Home}/{action=Index}/{id?}");
        }
    }
}

Update 3 - March 14, 2017 - Added csproj file

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup Label="Globals">
    <SccProjectName>SAK</SccProjectName>
    <SccProvider>SAK</SccProvider>
    <SccAuxPath>SAK</SccAuxPath>
    <SccLocalPath>SAK</SccLocalPath>
  </PropertyGroup>

  <PropertyGroup>
    <TargetFramework>netcoreapp1.1</TargetFramework>
    <PackageTargetFallback>portable-net45+win8</PackageTargetFallback>
  </PropertyGroup>

  <ItemGroup>
    <!--<Content Include="wwwroot\index.html" />-->
    <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="1.0.0" />
    <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="1.0.0" />
  </ItemGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.ApplicationInsights.AspNetCore" Version="2.0.0" />
    <PackageReference Include="Microsoft.AspNetCore" Version="1.1.1" />
    <PackageReference Include="Microsoft.AspNetCore.Mvc" Version="1.1.2" />
    <PackageReference Include="Microsoft.AspNetCore.StaticFiles" Version="1.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="1.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="1.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer.Design" Version="1.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="1.1.0" />
    <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="1.1.1" />
    <PackageReference Include="Microsoft.VisualStudio.Web.BrowserLink" Version="1.1.0" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="1.1.0" />
  </ItemGroup>
  <ItemGroup>
    <Folder Include="Controllers\" />
    <Folder Include="Data\" />
    <Folder Include="Views\Home\" />
    <Folder Include="wwwroot\images\" />
  </ItemGroup>

</Project>

Answer 1

How I resolve this in VS 2017|2019

• Remove EntityFramework (not EntityFrameworkCore) references from all projects in the solution
• Open the solution folder in Explorer (Windows Explorer)
• Close VS
• delete folder
• Open the solution again
• Run update-database and the alert is gone

You connot see '.vs' folder?

Answer 2

Perhaps you have at least two projects in your solution each one using either version of EF. By issuing "Manage NuGet packages for solution..." you can verify if this is the case. Then, maybe you'd need to sacrifice the one using EF 6.x. After that you'll need to restart VS, maybe some caching prevents removing the package completely when you uninstall it.

EDIT: .. or you may live well with both of them, but read carefully the message and follow what it says...

Answer 3

For those using the new port of Entity Framework 6.3 and later to .Net Core, there is a good chance that a solution will include both EfCore and Ef6 artifacts.

e.g. I had migrated an older EF6 repository from .Net Framework to Core, but wanted to make use of the out-of-the-box AspNet Identity Core subsystem, which uses EfCore.

Invariably, during migrations, I would aribtrarily receive errors like:

Both Entity Framework Core and Entity Framework 6 are installed. The Entity Framework Core tools are running. Use 'EntityFramework6\Update-Database' for Entity Framework 6.

or

Both Entity Framework 6 and Entity Framework Core are installed. The Entity Framework 6 tools are running. Use 'EntityFrameworkCore\Add-Migration' for Entity Framework Core

The solution is simple - when running migration commands, as per the warning, always qualify the commands with the fully qualified:

EntityFramework6\Add-Migration Foo
EntityFramework6\Update-Database

or

EntityFrameworkCore\Add-Migration Foo
EntityFrameworkCore\Update-Database

Note that for EF6 fans, at time of writing, the migration tools port to Core isn't quite up to scratch yet, as per here.

Similarly, if you have multiple DbContexts even in the same framework version (EfCore vs Ef6 on Core), you'll need to specify the name of the specific DbContext that you are trying to target, e.g.

EntityFramework6\Add-Migration Foo -Context BarDbContext
EntityFramework6\Add-Migration Baz -Context FooDbContext