MetadataException: Unable to load the specified metadata resource

This means that the application is unable to load the EDMX. There are several things which can cause this.

• You might have changed the MetadataArtifactProcessing property of the model to Copy to Output Directory.
• The connection string could be wrong. I know you say you haven't changed it, but if you have changed other things (say, the name of an assembly), it could still be wrong.
• You might be using a post-compile task to embed the EDMX in the assembly, which is no longer working for some reason.

In short, there is not really enough detail in your question to give an accurate answer, but hopefully these ideas should get you on the right track.

Update: I've written a blog post with more complete steps for troubleshooting.

A minor amendment helped me with this problem.

I had a solution with 3 project references:

connectionString="metadata=res://*/Model.Project.csdl|res://*/Model.Project.ssdl|res://*/Model.Project.msl;

which I changed to:

connectionString="metadata=res://*/;

You can get this exception when the Edmx is in one project and you are using it from another.

The reason is Res://*/ is a uri which points to resources in the CURRENT assembly. If the Edm is defined in a different assembly from the code which is using it, res://*/ is not going to work because the resource cannot be found.

Instead of specifying ‘*’, you need to provide the full name of the assembly instead (including public key token). Eg:

res://YourDataAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=abcdefabcedf/YourEdmxFileName.csdl|res://...

A better way to construct connection strings is with EntityConnectionStringBuilder:

public static string GetSqlCeConnectionString(string fileName)
{
    var csBuilder = new EntityConnectionStringBuilder();

    csBuilder.Provider = "System.Data.SqlServerCe.3.5";
    csBuilder.ProviderConnectionString = string.Format("Data Source={0};", fileName);

    csBuilder.Metadata = string.Format("res://{0}/YourEdmxFileName.csdl|res://{0}/YourEdmxFileName.ssdl|res://{0}/YourEdmxFileName.msl", 
        typeof(YourObjectContextType).Assembly.FullName);

    return csBuilder.ToString();
}

public static string GetSqlConnectionString(string serverName, string databaseName)
{
    SqlConnectionStringBuilder providerCs = new SqlConnectionStringBuilder();

    providerCs.DataSource = serverName;
    providerCs.InitialCatalog = databaseName;
    providerCs.IntegratedSecurity = true;

    var csBuilder = new EntityConnectionStringBuilder();

    csBuilder.Provider = "System.Data.SqlClient";
    csBuilder.ProviderConnectionString = providerCs.ToString();

    csBuilder.Metadata = string.Format("res://{0}/YourEdmxFileName.csdl|res://{0}/YourEdmxFileName.ssdl|res://{0}/YourEdmxFileName.msl",
        typeof(YourObjectContextType).Assembly.FullName);

    return csBuilder.ToString();
}

If you still encounter the exception, open the assembly in reflector and check the filenames for your .csdl, .ssdl and .msl files. When the resources have different names to the ones specified in the metadata value, it’s not going to work.

And a quick way to check the model name without Reflector.... look for the directory

...obj/{config output}/edmxResourcesToEmbed

and check that the .csdl, .msl, and .ssdl resource files are there. If they are in a sub-directory, the name of the sub-directory must be prepended to the model name.

For example, my three resource files are in a sub-directory Data, so my connection string had to be

metadata=res://*/Data.MyModel.csdl|res://*/Data.MyModel.ssdl|res://*/Data.MyModel.msl;

(versus metadata=res://*/MyModel.csdl|res://*/MyModel.ssdl|res://*/MyModel.msl;).

This happens to me when I do not clean solution before build new .edmx designer. So just don’t forget to clean solution before you build new .edmx designer. This helps me to skip lot more issues with this one. Bellow the navigation details provided incase you are new in visual studio.

Click->Build->Clean Solution

Then Click->Build->Rebuild Solution

Hope this helps. Thanks everyone

This happened to me when I accidentally switched the Build Action of the edmx file (appears under Properties in the IDE) from 'EntityDeploy' to 'None'. EntityDeploy is what populates the metadata for you: see http://msdn.microsoft.com/en-us/library/cc982037.aspx

If you are using the edmx from a different project, then in the connection string, change...

metadata=res://*/Data.DataModel.csdl

...to...

metadata=res://*/DataModel.csdl

I've just spent a happy 30 minutes with this. I'd renamed the entities object, renamed the entry in the config file, but there's more ... you have to change the reference to the csdl as well

very easy to miss - if you're renaming, make sure you get everything ....

Sometimes i see this error in my project. I solve that by

1 - Right click on EDMX file

2 - Select Run Custom Tool option

3 - Rebuild project

The ultimate solution (even after recreating the database on two other machines, as well as the EDMX and other sundries) was to not use the first edition of Entity Framework. Looking forward to evaluating it again in .NET 4.0.

After running into the same problem again and searching all over for an answer, I finally found someone who'd had the same problem. It appears that the connection string wasn't correctly generated by Visual Studio's wizard, and the link to the metadata resources was missing an important path.

v1.0 BUG?: Unable to load the specified metadata resource. Scripts != Models

Update 2013-01-16: Having transitioned to almost exclusively using EF Code First practices (even with existing databases) this problem is no longer an issue. For me, that was a viable solution to reducing the clutter from auto-generated code and configuration and increasing my own control over the product.

Had same issue because I renamed an assembly.

I had to also rename it in AssemblyTitle and AssemblyProduct attributes in project Properties/AssemblyInfo.cs, and also deleting and re adding the reference to the edmx file.

Then it worked just fine.

I also had the same problem and solution as per Rick, except that I was importing an existing .edmx to a new project, and while the base namespace didn't matter it was imported into a different subdirectory so I also had to update the connection string inside Web.Config in three places, to include the different subdirectory naming:

In my case none of the answers listed worked and so I'm posting this.

For my case, building on Visual studio and running it with IIS express worked fine. But when I was deploying using Nant scripts as a stand-alone website was giving errors. I tried all the suggestions above and then realized the DLL that was generated by the nant script was much smaller than the one generated by VS. And then I realized that Nant was unable to find the .csdl, .msl and .ssdl files. So then there are really two ways to solve this issue, one is to copy the needed files after visual studio generates them and include these files in the build deployment. And then in Web.config, specify path as:

"metadata=~/bin/MyDbContext.csdl|~/bin/MyDbContext.ssdl|~/bin/MyDbContext.msl;provider=System.Data.SqlClient;...."

This is assuming you have manually copied the files into bin directory of the website which you are running. If it's in a different directory, then modify path accordingly. Second method is to execute EdmGen.exe in Nant script and generate the files and then include them as resources like done in the example below: https://github.com/qwer/budget/blob/master/nant.build

My theory is that if you have more than one edmx file with same name (Model1 for example), it will give that exception. I've got same problem when I decided to name all my edmx files (sitting in different projects) as Model1 because I thought they should be independent.

I got this problem after moving a large solution from one folder in Source Control Explorer to another. We don't check the package folder into Team Foundation and so I think VS downloaded packages automatically. This upgraded my EF form v6.1.2 to v6.1.3.

The problem went away when I downgraded to the original v6.1.2.

I had same issue on 27 Sep 2019.

My API is in Dot net core Targeting to .net framework. edmx is in a different class library which is in .net framework only.

I observed that when I try to call that edmx from API .. for some reason I got that error.

What I did is, go to the obj folder of API and delete everything. then clean the API project and try again and that worked for me.

I was reflecting an old program, I faced the same problem. I went through previous answers, and I succeeded to solve it by putting the 3 files of "Model.csdl", "Model.ssdl" and "Model.msl" in the bin directory, and also beside the entities class. After that change the metdata part of the entities connection string in web.config to be:

metadata=~/bin/Model.csdl|~/bin/Model.ssdl|~/bin/Model.msl

and the program ran successfully withput displaying this exception.

i deleted the \bin and \obj folders from all of the projects in the solution, then rebuilt the soluition and it worked fine