Error message 'Unable to load one or more of t

Question

I have developed an application using Entity Framework, SQL Server 2000, Visual Studio 2008 and Enterprise Library.

It works absolutely fine locally, but when I deploy the project to our test environment, I am getting the following error:

Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information

Stack trace: at System.Reflection.Module._GetTypesInternal(StackCrawlMark& stackMark)

at System.Reflection.Assembly.GetTypes()

at System.Data.Metadata.Edm.ObjectItemCollection.AssemblyCacheEntry.LoadTypesFromAssembly(LoadingContext context)

at System.Data.Metadata.Edm.ObjectItemCollection.AssemblyCacheEntry.InternalLoadAssemblyFromCache(LoadingContext context)

at System.Data.Metadata.Edm.ObjectItemCollection.AssemblyCacheEntry.LoadAssemblyFromCache(Assembly assembly, Boolean loadReferencedAssemblies, Dictionary2 knownAssemblies, Dictionary2& typesInLoading, List`1& errors)

at System.Data.Metadata.Edm.ObjectItemCollection.LoadAssemblyFromCache(ObjectItemCollection objectItemCollection, Assembly assembly, Boolean loadReferencedAssemblies)

at System.Data.Metadata.Edm.ObjectItemCollection.LoadAssemblyForType(Type type)

at System.Data.Metadata.Edm.MetadataWorkspace.LoadAssemblyForType(Type type, Assembly callingAssembly)

at System.Data.Objects.ObjectContext.CreateQuery[T](String queryString, ObjectParameter[] parameters)

Entity Framework seems to have issue, any clue how to fix it?

Answer 1

Set 32 bit IIS mode to true, debug mode to true in the configuration file, deleting the temp directory and resetting IIS fixes the issue temporally and it comes back after some time.

Answer 2

I build a few projects for SharePoint and, of course, deployed them. One time it happened.

I found an old assembly in C:\Windows\assembly\temp\xxx (with FarManager), removed it after reboot, and all projects built.

I have question for MSBuild, because in project assemblies linked like projects and every assembly is marked "Copy local", but not from the GAC.

Answer 3

If you are using Entity Framework, try copying the following references locally.

• System.Data.Entity
• System.Web.Entity

Change the property "Copy Local" to "True" for these references and publish.

Answer 4

I encountered this error with an ASP.NET 4 + SQL Server 2008 R2 + Entity Framework 4 application.

It would work fine on my development machine (Windows Vista 64-bit). Then when deployed to the server (Windows Server 2008 R2 SP1), it would work until the session timed out. So we'd deploy the application and everything looked fine and then leave it for more than the 20 minute session timeout and then this error would be thrown.

To solve it, I used this code on Ken Cox's blog to retrieve the LoaderExceptions property.

For my situation the missing DLL was Microsoft.ReportViewer.ProcessingObjectModel (version 10). This DLL needs to be installed in the GAC of the machine the application runs on. You can find it in the Microsoft Report Viewer 2010 Redistributable Package available on the Microsoft download site.

Answer 5

Other suggestions are all good. In my case, the problem was that the developer box was a 64-bit machine using the x86 location of various APIs, including Silverlight.

By changing the target platform to match the 32-bit server where the web application was being deployed removed the majority of the errors related to not being able to load one or more of the requested types.

Answer 6

I had the same issue (but on my local) when I was trying to add Entity Framework migration with Package Manager Console.

The way I solved it was by creating a console application where Main() had the following code:

 var dbConfig = new Configuration();
 var dbMigrator = new DbMigrator(dbConfig);
 dbMigrator.Update();

Make sure the Configuration class is the migration Configuration of your failing project. You will need System.Data.Entity.Migrations to use DbMigrator.

Set a breakpoint in your application, and run it. The exception should be caught by Visual Studio (unless you have that exception type set to not break the debug session), and you should be able to find the info you are looking for.

The missing reference in my case was EFProviderWrapperToolkit.