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

I also got this issue when create new Microsoft Word add-in with Visual Studio 2015. The issue is about I have 2 versions of MS Office, 2013 and 2016. I uninstall MS Office 2013 and then it works.

Answer 2

Make sure you allow 32 bits applications on IIS if you did deploy to IIS. You can define this on the settings of your current Application Pool.

Answer 3

I had the same error message reported when compiling a Visual Studio package (VSPackage). The whole solution compiles and the error is thrown when the package is being created by CreatePkgDef. Having said that, it is clear that I cannot catch the LoaderExceptions as it is not my application that throws it, but Microsoft's own tool. (Though I am responsible for the confusion of CreatePkgDef.)

In my case the root cause was that my solution creates a MyDll.dll that has already been registered to the GAC (and they are different), so the CreatePgkDef got confused which one to use and it decided just to throw an error which isn't really helpful. The MyDll.dll in the GAC was registered by the installer of the same product (obviously an earlier version, with /slightly/ different content).

How to fix it

1. Preferred way: Make sure you use the correct version of MyDll.dll
   2. When compiling your project make sure you use a different version number than you used in the previous version located in the GAC. Make sure the following attributes are correct:
      • [assembly: AssemblyVersion("1.0.0.1")] // Assuming the old DLL file was versioned 1.0.0.0
      • [assembly: AssemblyFileVersion("1.0.0.1")] // Assuming the old DLL file was versioned 1.0.0.0
   3. If needed, specify the fully qualified assembly name (for example, "MyDll.dll, Version=1.0.0.1, Culture=neutral, PublicKeyToken=1234567890abcdef") when you reference it in your other projects.
2. If the above failed: You can uninstall the old MyDll.dll from GAC
   1. How to Uninstall an Assembly from the GAC
   2. Uninstall the application that includes MyDll.dll

Changing the AssemblyVersion was good enough for me. :)

I hope this was helpful.

Answer 4

In case none of the other answers help you:

When I had this problem, it turned out my Windows service was built for an x64 platform, and I was inadvertently running the 32-bit version of InstallUtil.exe. So make sure you're using the right version of InstallUtil for the platform you built for.

Answer 5

My issue has been resolved after I deleted the redundant assembly files from the bin folder.

Answer 6

As it has been mentioned before, it's usually the case of an assembly not being there.

To know exactly what assembly you're missing, attach your debugger, set a breakpoint and when you see the exception object, drill down to the 'LoaderExceptions' property. The missing assembly should be there.

Hope it helps!