Hi Connie

What is the details of the exception?

/Jan

I'll try this again. Last night when I tried to post the stack trace, the forum puked and lost my message.

[TypeLoadException: Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.]
   System.ModuleHandle.ResolveType(RuntimeModule module, Int32 typeToken, IntPtr* typeInstArgs, Int32 typeInstCount, IntPtr* methodInstArgs, Int32 methodInstCount, ObjectHandleOnStack type) +0
   System.ModuleHandle.ResolveTypeHandleInternal(RuntimeModule module, Int32 typeToken, RuntimeTypeHandle[] typeInstantiationContext, RuntimeTypeHandle[] methodInstantiationContext) +180
   System.Reflection.RuntimeModule.ResolveType(Int32 metadataToken, Type[] genericTypeArguments, Type[] genericMethodArguments) +192
   System.Reflection.CustomAttribute.FilterCustomAttributeRecord(CustomAttributeRecord caRecord, MetadataImport scope, Assembly& lastAptcaOkAssembly, RuntimeModule decoratedModule, MetadataToken decoratedToken, RuntimeType attributeFilterType, Boolean mustBeInheritable, Object[] attributes, IList derivedAttributes, RuntimeType& attributeType, IRuntimeMethodInfo& ctor, Boolean& ctorHasParameters, Boolean& isVarArg) +115
   System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeModule decoratedModule, Int32 decoratedMetadataToken, Int32 pcaCount, RuntimeType attributeFilterType, Boolean mustBeInheritable, IList derivedAttributes, Boolean isDecoratedTargetSecurityTransparent) +426
   System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeAssembly assembly, RuntimeType caType) +103
   System.Reflection.RuntimeAssembly.GetCustomAttributes(Type attributeType, Boolean inherit) +64
   WebActivator.AssemblyExtensions.GetActivationAttributes(Assembly assembly) +126
   WebActivator.ActivationManager.RunActivationMethods() +216
   WebActivator.ActivationManager.RunPreStartMethods() +28
   WebActivator.ActivationManager.Run() +55

[InvalidOperationException: The pre-application start initialization method Run on type WebActivator.ActivationManager threw an exception with the following error message: Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'..]
   System.Web.Compilation.BuildManager.InvokePreStartInitMethods(ICollection`1 methods) +423
   System.Web.Compilation.BuildManager.CallPreStartInitMethods() +306
   System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +677

[HttpException (0x80004005): The pre-application start initialization method Run on type WebActivator.ActivationManager threw an exception with the following error message: Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'..]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +9088796
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +97
   System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +258

I narrowed it down to an issue with changes in ClientDependency.Core.dll. Version 1.7.0.4 is provided with Umbraco 6.1.4 while version 1.8.2.1 is provided with Umbraco 6.1.5+

I copied the older version back to the server and everything seems to run fine. Anyone know what the differences are between these?

Additional update: The version of ClientDependency.Core.dll that ships with Umbraco 6.1.5+ is complied for .NET 4.5. Via this security alert I was able to download the updated but .NET 4 version that is compatible with my server.

http://umbraco.com/follow-us/blog-archive/2015/2/5/security-alert-update-clientdependency-immediately

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