Entity Framework Provider type could not be loaded?

Question

I am trying to run my tests on TeamCity which is currently installed on my machine.

System.InvalidOperationException:

The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' for the 'System.Data.SqlClient' ADO.NET provider could not be loaded. Make sure the provider assembly is available to the running application.

See http://go.microsoft.com/fwlink/?LinkId=260882 for more information..

I have no reference to System.Data.Entity in any of my projects as was suggested on codeplex for upgrading to EF6.

So, I am not sure why am I getting this exception. I do not get any such exception when I run the tests from VS.

I did try to set CopyLocal to false then again to true.. but that does not seem to work either.

Update

My app.config has the following . Does this cause some behavior that I don't understand ?

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
  </configSections>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
  </entityFramework>
</configuration>

I get the following stacktrace in teamcity .

[MSTest] IntegrationTests.CrudTest+QuestionTest.Create
[03:59:11][IntegrationTests.CrudTest+QuestionTest.Create] Initialization method IntegrationTests.CrudTest+QuestionTest.Initialize threw exception. System.InvalidOperationException: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' for the 'System.Data.SqlClient' ADO.NET provider could not be loaded. Make sure the provider assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information..
[03:59:11]
[IntegrationTests.CrudTest+QuestionTest.Create]     at System.Data.Entity.Config.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName)
   at System.Data.Entity.Config.ProviderServicesFactory.GetInstanceByConvention(String providerInvariantName)
   at System.Data.Entity.Config.DefaultProviderServicesResolver.GetService(Type type, Object key)
   at System.Data.Entity.Config.CachingDependencyResolver.<>c__DisplayClass1.<GetService>b__0(Tuple`2 k)
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at System.Data.Entity.Config.CachingDependencyResolver.GetService(Type type, Object key)
   at System.Data.Entity.Config.ResolverChain.<>c__DisplayClass3.<GetService>b__0(IDbDependencyResolver r)
   at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
   at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source, Func`2 predicate)
   at System.Data.Entity.Config.ResolverChain.GetService(Type type, Object key)
   at System.Data.Entity.Config.RootDependencyResolver.GetService(Type type, Object key)
   at System.Data.Entity.Config.ResolverChain.<>c__DisplayClass3.<GetService>b__0(IDbDependencyResolver r)
   at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
   at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source, Func`2 predicate)
   at System.Data.Entity.Config.ResolverChain.GetService(Type type, Object key)
   at System.Data.Entity.Config.CompositeResolver`2.GetService(Type type, Object key)
   at System.Data.Entity.Config.IDbDependencyResolverExtensions.GetService[T](IDbDependencyResolver resolver, Object key)
   at System.Data.Entity.Config.InternalConfiguration.GetService[TService](Object key)
   at System.Data.Entity.Config.DbConfiguration.GetService[TService](Object key)
   at System.Data.Entity.Utilities.DbProviderFactoryExtensions.GetProviderServices(DbProviderFactory factory)
   at System.Data.Entity.Infrastructure.DefaultManifestTokenService.GetProviderManifestToken(DbConnection connection)
   at System.Data.Entity.Utilities.DbConnectionExtensions.GetProviderInfo(DbConnection connection, DbProviderManifest& providerManifest)
   at System.Data.Entity.DbModelBuilder.Build(DbConnection providerConnection)
   at System.Data.Entity.Internal.LazyInternalContext.CreateModel(LazyInternalContext internalContext)
   at System.Data.Entity.Internal.RetryLazy`2.GetValue(TInput input)
   at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
   at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
   at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
   at System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
   at System.Data.Entity.Internal.Linq.InternalSet`1.ActOnSet(Action action, EntityState newState, Object entity, String methodName)
   at System.Data.Entity.Internal.Linq.InternalSet`1.Add(Object entity)
   at System.Data.Entity.DbSet`1.Add(TEntity entity)
   at EFRepository.Infrastructure.EFRepository`1.Add(T item) in c:\TeamCity\buildAgent\work\da2ea4e72c0e77f0\Repository\Infrastructure\EFRepository.cs:line 22
   at IntegrationTests.CrudTest.Initialize() in c:\TeamCity\buildAgent\work\da2ea4e72c0e77f0\IntegrationTests\CrudTest.cs:line 34

Dorsum

Is EntityFramework.SqlServer.dll deployed along with EntityFramework.dll? In EF6 SqlServer and SqlServerCE providers are not in the same assembly as the EF engine as it was with previous versions. You should not add a reference to the System.Data.Entity.dll. The provider model in EF6 changed compared to EF5 and EF5 provider will just not work. In addition you can hit a few tricky problems (like EF5 geospatial types treated as entity types in EF6) – Sepaloid

Yes I have double checked there is no reference to System.Data.Entity and the references to both EntityFramework.dll and EntityFramework.SqlServer.dll are present. Again the projetc compiles and tests run in VS. It is only when I the tests run on TeamCity that the error crops up. – Dorsum

This is a correct setup. I have not used TeamCity but it appears to me that when your app is deployed to run the tests with TeamCity the EntityFramework.SqlServer.dll is missing and hence the exception. – Sepaloid

I have removed bin from my gitignorelist .. it still throws the same error.. any ideas where it is trying to look for the dlls ? – Dorsum

Here is how the runtime locates assemblies - msdn.microsoft.com/en-us/library/yx7xezcf.aspx. I would just just start looking in the same folder where your app and the EntityFramework.dll on the TeamCity server is. – Sepaloid

@Sepaloid I have put the code up here github.com/ashutoshraina/Pariksha ..can you see if you can find the issue. The path to the test seems to be ok since TeamCity is picking it up correctly. – Dorsum

I did not spot anything wrong with your project. Can you share the stack trace? I wonder where the call originated from... – Sepaloid

No, this was not resolved. Tried all sorts of things. Yet to find a solution. – Dorsum

see the answer from this post: #21176213 I added the private volatile Type _dependency... answer and it worked! It just stinks that I have to add a separate class like this just to get EF to work in TeamCity. – Rubin

I uninstalled EntityFramework from nuget packages and installed again and it got fixed – Seta

You need to manually add the reference to these assemblies. EntityFramework, EntityFramework.SqlServer – Fishhook

Answer 1

Same problem, but i installed EF 6 through Nuget. EntityFramework.SqlServer was missing for another executable. I simply added the nuget package to that project.

Praenomen

I noticed this too. If you create a library that uses EF, VS will put the EF.dll and the EF.SqlServer.dll into that build folder. But if you now have another program make use of your library, only the EF.dll will be put into this build folder. The EF.SqlServer.dll is missing. If you add it manually to the build folder, the program works. Not a good solution in itself, but shows the problem is the EF.SQLServer.dll missing is the cause of the error. – Absorption

I added var x = typeof(System.Data.Entity.SqlServer.SqlProviderServices); Then my app worked – Libenson

I always worry when I type code in that does absolutely nothing and all the sudden my project runs. O_o – If

Also, because of compiler optimization you might want to also do x.ToString() or it will take out the typeofs in Release. – If

I find it annoying that EF 6.1 now needs EF installed on my ASPX DLL/Project, whereas EF 5.0 only needed it on my data-layer DLL/Project. – Counterclockwise

Ended up just adding the EntityFramework.SqlServer.dll manually to the project from packages folder. – Ritz

You just don't want all your projects have EF as a reference, since the Datalayer of your application must solve the problem. The solution of Robert Muehsig solves the bug in EF. I placed his code in my DBcontext file. Even sometimes it's even not possible to include all projects with EF because you are not building all the projects which are calling the datalayer. – Launder

I searched in Nuget for "EntityFramework.SqlServer" and there are no results. Where is the package? Not listed in the installed list either – Mouton

Incidentally, GC.KeepAlive is a better solution for "I need to reference something" than random variables and ToStrings – Schechinger

I cannot load EntityFramework.SqlServer.dll even if it is there in the bin directory (without me copying it to that location) – Gloxinia

I needed to remove EF and then re add it for this to take. – Daph

If anyone run into the problem after removing the EntityFramework.SqlServer reference from your project, just add it back. It should be located in YourSolutionDir\packages\EntityFramework.6.0.0\lib\net45\EntityFramework.SqlServer.dll. But.. I'm just wondering why it is needed for EntityFramework even if we do not use SqlServer. – Schadenfreude

You may additionally need to add [DeploymentItem("EntityFramework.SqlServer.dll")] and [DeploymentItem("EntityFramework.dll")] to as attributes to your unit test class if the file is still not being copied after you add it as a reference. – Nimrod

Add the same entity framework reference in config located project ,One situation I have faced , EF created in one class library and web config file located in my UI project, Add the same reference add UI then work fine – Cytochrome

The package is now unlisted. It appears to have been a pre-release version that never made it to an official release? – Socle

You need to manually add the reference to these assemblies. EntityFramework, EntityFramework.SqlServer – Fishhook

1000 downvotes to microsoft- why my tester needs EF references ? – Radmilla

Answer 2

I had the same problem in my Test projects - I installed the latest EF6 bits via NuGet and everytime I invoke something EF-related I got:

The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' for the 'System.Data.SqlClient' ADO.NET provider could not be loaded. Make sure the provider assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information.

My workaround: I placed this method inside my test project:

public void FixEfProviderServicesProblem()
{
//The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer'
//for the 'System.Data.SqlClient' ADO.NET provider could not be loaded. 
//Make sure the provider assembly is available to the running application. 
//See http://go.microsoft.com/fwlink/?LinkId=260882 for more information.

var instance = System.Data.Entity.SqlServer.SqlProviderServices.Instance;
}

This method is never been called, but I think the compiler will remove all "unnecessary" assemblies and without using the EntityFramework.SqlServer stuff the test fails.

Anyways: Works on my machine ;)

Note: Instead of adding the method to test project you can ensure a static reference to SqlProviderServices from your Model/entity project.

Metaphase

I ended up doing the same. I would like to speak to that person who made this assembly a dependency on opening a connection to db. In their alternate universe all of our frontend projects that have config file with a connection string should reference EntityFramework just to get this one dll to open the connection. In what way does this make sense I do not understand. – Spheno

It's a hack, but it's the best/easiest solution I've found for the scenario in which you don't have a deployment package created for your project. – Givens

For all of you using other suggestions like "var x = typeof(SqlProviderServices);". Only this solution provided by Robert works on development and build machines!!! – Rennet

This worked for me too..Here is how my entityFramework node looks like in config <entityFramework> <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" /> <providers> <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" /> </providers> </entityFramework> – Cronyism

To be clear: Adding the above code to your DbContext class will solve the problem in EF 6.1. This way you don't need to include the Entity Framework Nuget package in your front-end (WebApi, etc) project and can leave everything EF-related in your data layer. – Catechin

@AndersLindén, You should place the reference in code in your data context/ entities project. See https://mcmap.net/q/64234/-no-entity-framework-provider-found-for-the-ado-net-provider-with-invariant-name-39-system-data-sqlclient-39 – Clubman

Still an issue in VS 2017, EF 6.2. Adding the line mentioned above in the test class will solve the problem, you do not need to polute your DbContext – Velar

VS 2017, EF 6.2 here, opted to put this method at the bottom of the DbContext because maintaining "separation of concerns" in our assemblies is worth the bit of extra code. – Still

To bad that anno 2022 this still is the best solution for EF 6.4.4 – Fraught

Answer 3

Nuget will configure your EF6 project to reference EntityFramework.SqlServer.dll. This deploys to the output folder for your EF6 project during build, but it will not deploy to the output folder for projects referencing your EF6 project. I believe this is because Visual Studio is "smart" enough to detect that nothing in your assembly is actually using the dll directly and so does not include it. You can force EntityFramework.SqlServer.dll to be deployed to the output folder of projects referencing your EF6 project (unit tests, UI's etc.) by adding code to your EF6 project that uses EntityFramework.SqlServer.dll. Be careful not to put the code in a generated class as you risk losing it on next regen. I chose to add the following class to the assembly, which fixed the problem.

using System.Data.Entity.SqlServer;

internal static class MissingDllHack
{
    // Must reference a type in EntityFramework.SqlServer.dll so that this dll will be
    // included in the output folder of referencing projects without requiring a direct 
    // dependency on Entity Framework. See https://mcmap.net/q/65608/-entity-framework-provider-type-could-not-be-loaded.
    private static SqlProviderServices instance = SqlProviderServices.Instance;
}

Wastebasket

This solved the issue for me with respect to MSTest. I like this method because it doesn't require that I do anything messy with class inheritance on my test classes. Just include the class somewhere in the test assembly and MAGIC. Thanks! – Kenna

Exactly, this is the reason it is not copying the sqlserver.dll to the referencing projects output. This happens when you have one more layer in between executing application and Context assembly. Thanks this solved my issue. – Equality

For those not wanting to spend 4 seconds looking it up: using System.Data.Entity.SqlServer; – Lefler

We use a common base class for unit tests, all unit tests inherit from this class. Adding this method to that one class means that all projects with a unit test class inheriting from the base class work OK. – Sirup

Small point, but it's probably best to add a comment to this class to explain why it is necessary. – Piece

@JD41 Agreed. Including the 'share' link for this answer with the text "For more info" might be enough, but a detailed explanation of a few sentences would be very polite to future sanity. – Forefinger

Answer 4

My solution was to remove the entity framework from the project via the nuget manager and add it back in.

Pauperism

PM> Update-Package -Reinstall "EntityFramework" -ProjectName "MyProj1" – Caviar

This worked out for me, and I think it might be the optimal solution – Retraction

Simple, clean solution that works. Should be much higher on the list – Drippy

Same here. Thanks! And thank you @Caviar for the command. – Su

Answer 5

I solved this by adding an using stament on top of my DBContext class, like so:

using SqlProviderServices= System.Data.Entity.SqlServer.SqlProviderServices;

Cruck

This is the cleanest solution to this problem. Thank you. – Gotham

This solution works and looks clean. Question: wont we loose the line id the DBContext class is refreshed? i.e. using the edmx class generation? – Hebron

Can't believe this was necessary and somehow hasn't been corrected by Microsoft - but this worked for me. Thanks for a simple solution. – Earleneearley

This solution is functionally the same as MissingDllHack. It may seem cleaner, but introduces workaround code into your context class. This code will also be flagged for removal by tools like ReSharper and could easily be lost over time. A good solution, but I prefer to keep the workaround separate from the context in a way that does not produce code warnings. – Wastebasket

Answer 6

I've used Code-based registration for provider. link1 link2

Just created the configuration class like

class DbContextConfiguration : DbConfiguration
{
    public DbContextConfiguration()
    {
        this.SetDatabaseInitializer(new DropCreateDatabaseAlways<MyDbContext>());
        this.SetProviderServices(SqlProviderServices.ProviderInvariantName, SqlProviderServices.Instance);
    }
}

Key point is this.SetProviderServices(SqlProviderServices.ProviderInvariantName, SqlProviderServices.Instance);

and used it in the such way

[DbConfigurationType(typeof(DbContextConfiguration))]
public class MyDbContext : DbContext
{
    public MyDbContext()
    {
        ...
    }

    public DbSet<...> ...{ get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        ...
    }
}

Jack

I have two projects in one solution. The first is the class-library with the entity framework assembly an the DbContext class and the tt-files. The second project is windows forms that should get data by using the ef-project. @Nash: Could you elaborate where (into which project) you placed your class DbContextConfiguration? Thanks – Cassandracassandre

As mentioned above it seems that additional references are one way to fix this (see comment from eric). I used the nuget console and fired this command: Get-Project MyWinformsProject | Install-Package EntityFramework which fixed it for me. Still i would like to better understand the reason. – Cassandracassandre

DbContextConfiguration seemed to already be present (vs 2013), adding the DbConfiguraton line above my MyDbContext class did not solve the issue for me. – Gloxinia

You don't need a DbConfiguration class. Put the following code at app startup (before EF is used): DbConfiguration.Loaded += (sender, e) => e.ReplaceService<DbProviderServices>((s, k) => System.Data.Entity.SqlServer.SqlProviderServices.Instance);. – Loudish

Answer 7

I sorted it out with [DeploymentItem] on my assembly initializing class

namespace MyTests
{
    /// <summary>
    /// Summary description for AssemblyTestInit
    /// </summary>
    [TestClass]
    [DeploymentItem("EntityFramework.SqlServer.dll")]
    public class AssemblyTestInit
    {
        public AssemblyTestInit()
        {
        }

        private TestContext testContextInstance;

        public TestContext TestContext
        {
            get
            {
                return testContextInstance;
            }
            set
            {
                testContextInstance = value;
            }
        }

        [AssemblyInitialize()]
        public static void DbContextInitialize(TestContext testContext)
        {
            Database.SetInitializer<TestContext>(new TestContextInitializer());
        }
    }
}

Masjid

Answer 8

Late to the party, but the top voted answers all seemed like hacks to me.

All I did was remove the following from my app.config in the test project. Worked.

  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="mssqllocaldb" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>

Fecula

The real solution! – Filiate

All I did was remove the <provider ... SqlClient...> in my case. And that worked here as well. – Deneb

Answer 9

I had a similar problem, because I didn't add reference to EntityFramework.sqlServer.dll. When I run program from vs, it worked. But when I publish app and install it, it throws error.

Rebuild after adding it into the reference fixed the problem.

Giulio

I did this one and its worked. Basically the project will show an warning when the components to the libraries where not referred properly. – Fishhook

Answer 10

I have solved this by manually copying EntityFramework.SqlServer.dll file to the bin folder of the main application.

Kloster

Answer 11

I had same isssue i tried many times but it did not resolve but when i install the package EntityFramework.SqlServerCompact it solved install this package from Nuget package Manager.

Install-Package EntityFramework.SqlServerCompact

Deluge

Answer 12

I finally resolved this. Turns out, I had an erroneous implementation of IDIsposable in my repository class. I fixed that. The erroneous implementation caused a stackoverflow exception since I wasn't disposing off resources properly. This caused VS not to run the tests and the test execution engine crashed.

I filed it with Microsoft here ( this was before I got the correct solution). connect.microsoft.com/VisualStudio/feedback/details/775868/vs-test-execution-crashes-in-vs-2012#details

Anyway, the builds now run fine on teamcity. ALthough, I am still curious why neither VS Test execution engine had a graceful way of telling me what was happening not Team City.

I discovered the root cause by manually debugging the test ( which I only realised after so many days , the fix took me 5 seconds).

Hopefully this will help someone who comes across such issues.

Dorsum

Answer 13

I see similar problem, and using the method from this post: (http://entityframework.codeplex.com/workitem/1590), which solves my problem.

To work around the issue you can make your test assembly directly reference the provider assembly by adding some line like this anywhere in the test assembly: var _ = System.Data.Entity.SqlServer.SqlProviderServices.Instance;

Radial

Answer 14

I've created a static "startup" file and added the code to force the DLL to be copied to the bin folder in it as a way to separate this 'configuration'.


[DbConfigurationType(typeof(DbContextConfiguration))] public static class Startup { }

public class DbContextConfiguration : DbConfiguration
{
    public DbContextConfiguration()
    {
        // This is needed to force the EntityFramework.SqlServer DLL to be copied to the bin folder
        SetProviderServices(SqlProviderServices.ProviderInvariantName, SqlProviderServices.Instance);
    }
}

Sycamine

Thanks! This was a huge help. – Threlkeld

Glad that you've found my answer helpful @AddisonSchuhardt :) – Sycamine

This was a huge help... and pro tip for anyone still looking at using multiple EF 6 contexts, you may have to add manual reference to EntityFramework.SqlServer.dll in your project and add this class to the config file in the node <entityFramework codeConfigurationType="........">example</entityFramework>. – Anderer

Answer 15

When I inspected the problem, I have noticed that the following dll were missing in the output folder. The simple solution is copy Entityframework.dll and Entityframework.sqlserver.dll with the app.config to the output folder if the application is on debug mode. At the same time change, the build option parameter "Copy to output folder" of app.config to copy always. This will solve your problem.

Limit

I set up "Copy Local" true for "EntityFramework.SqlServer" only. Now it works. – Chuddar

Answer 16

Simply reference or browser the EF dll - EntityFramework.SqlServer.dll

Altazimuth

This is what I did. Copied the Reference to "EntityFramework.SqlServer" from my library to the "running" project. That worked! – Immobile

Answer 17

After trying all other suggested solutions and don't getting my project to work, I finally found a little comment in this page:

Deleting the BIN-Folder did it for me

And it worked for me too.

Caressive

I was merging 2 branches - my project had no changes related to EF, but my unittests just started failing for no reason. Deleting the BIN folder got them working again. – Aorangi

@Zeek2 this error is a tricky one. There are many different suggestions to solve this issue in the page I’ve quoted. This is just one of many possible solutions. Keep researching it until you find the solution which will apply to your particular issue, and good luck. – Caressive

Really weird that this was my solution too. – Gonnella

Answer 18

I didn't want a reference to EF in my application project (or to manually copy anything) so I added this to my EF project's Post-build events:

cp $(TargetDir)EntityFramework.SqlServer.dll $(SolutionDir){your-main-bin-folder}

Brede

Answer 19

This only happens inside my load/unit testing projects. Frustrating, I jyst had it crop up in a project I have been running for 2 years. Must have been some order of test running that breaks things. I guess once that fi gets removed its gone.

I found that simply declaring a variable that uses the correct value fixes the issue... I never even call the method. Just define it. Odd but it works.

    /// <summary>
    /// So that the test runner copies dlls not directly referenced by the integration project
    /// </summary>
    private void referenceLibs()
    {
        var useless = SqlProviderServices.Instance;
    }

Thankyou

Answer 20

I also had a similar problem

My problem was solved by doing the following:

Diverticulosis

Answer 21

I had the same issue with Instantiating DBContext object from a unit test project. I checked my unit test project packages and I figured that EntityFramework package was not installed, I installed that from Nuget and problem solved (I think it's EF bug).

happy coding

Abbatial

Answer 22

Adding Entityframework.dll and Entityframework.sqlserver.dll to the reference project solved the issue.

Gillmore

yes, I believe my csproj file was somehow referencing 6.0.0 when my packages.config was pointing to 6.1.3 (due to me moving some furniture around) – Asyut

Answer 23

I checked Debug Output window in Unit Test project. EntityFramework.SqlServer.dll was not loaded. After adding it to the bin folder tests were run successfully.

Hercule

Answer 24

I just had the same error message.

I have a separate project for my data access. Running the Web Project (which referenced the data project) locally worked just fine. But when I deployed the web project to azure the assembly: EntityFramework.SqlServer was not copied. I just added the reference to the web project and redeployed, now it works.

hope this helps others

Adel

Answer 25

I was working on the Contoso University tutorial offline and encountered the same issue when trying to create my first controller using EF. I had to use the Package Manager Console to load EF from the nuget cache and created a connection string to my local instance of SQL Server, my point here is my webConfig setting for EF may not be set as you all out there but I was able to resolve my issue by completely deleting the "providers" section within "entityFramework"

Robert

Equalizer

Answer 26

There is a easy fix. open the references in your project, right click "System.Data" -> properties. Change "Copy Local" to "True".

Problem should be fixed.

Hensley

Answer 27

In my case I resolved the problem by installing SQL Server 2012 Developer Edition when I had previously installed SQL Server Express 2012 (x64). It seems that provided me with the missing dependency.

Panteutonism

Answer 28

remove the entity framework from the project via nuget then add it back in.

Monotheism

Answer 29

In my case dll was not copied although I added a reference to it. This is because EntityFramework.SqlServer.dllis not copied into your project. Add that dll and it will hopefully work.You can find that from the project where you added datamodel.

Retinue

Answer 30

Additional to all useful suggestions here, if you are using EF 6.1.3, get sure your project's .net version is 4.5 or more.

Conlee

Answer 31

The problem in my case was that in order to catch another exception I had enabled common language runtime (CLR) exceptions. And I forgot to disable it.

I disabled it in my exception setting. and it overlooked this exception and went on to run and create a db for me (in my case) automatically.

Midtown

Answer 32

Make sure EntityFramework.dll, EntityFramework.SqlServer.dll and your provider's dll (for SQL Server Compact, that will EntityFramework.SqlServerCompact.dll) are in the deployed application folder. This is especially important for deployed application.

Doralynne

Answer 33

I had encountered exactly the same problem on my CI build server (running Bamboo), which doesn't install any Visual Studio IDE on it.

Without making any code changing for the build/test process (which I don't think is good solution), the best way is to copy the EntityFramework.SqlServer.dll and paste it to C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE. (where your mstest running)

Problem solved!

Commutator

Answer 34

Click on Reference> check EntityFramework Reference is present or not

If not available Add it

Click on

Add Reference > Add entity framework 1)EntityFrameWork 2)EntityFrameWork.SqlServer

Irishirishism