The "ValidateXaml" task failed unexpectedly error

[Alex Wu]

I created an empty silverlight application, run it and works. But after adding a reference to Telerik.Windows.Controls I get compiler error below. I did not do any coding nor add any controls to the project.I have already tried uninstalling all silverlight related softwares and reinstall Telerik.

Error    1    The "ValidateXaml" task failed unexpectedly.
System.IO.FileNotFoundException: Could not load file or assembly 'System.Core, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' or one of its dependencies. The system cannot find the file specified.
File name: 'System.Core, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e'
   at System.ModuleHandle.ResolveType(Int32 typeToken, RuntimeTypeHandle* typeInstArgs, Int32 typeInstCount, RuntimeTypeHandle* methodInstArgs, Int32 methodInstCount)
   at System.ModuleHandle.ResolveTypeHandle(Int32 typeToken, RuntimeTypeHandle[] typeInstantiationContext, RuntimeTypeHandle[] methodInstantiationContext)
   at System.Reflection.Module.ResolveType(Int32 metadataToken, Type[] genericTypeArguments, Type[] genericMethodArguments)
   at System.Reflection.CustomAttribute.FilterCustomAttributeRecord(CustomAttributeRecord caRecord, MetadataImport scope, Assembly& lastAptcaOkAssembly, Module decoratedModule, MetadataToken decoratedToken, RuntimeType attributeFilterType, Boolean mustBeInheritable, Object[] attributes, IList derivedAttributes, RuntimeType& attributeType, RuntimeMethodHandle& ctor, Boolean& ctorHasParameters, Boolean& isVarArg)
   at System.Reflection.CustomAttribute.GetCustomAttributes(Module decoratedModule, Int32 decoratedMetadataToken, Int32 pcaCount, RuntimeType attributeFilterType, Boolean mustBeInheritable, IList derivedAttributes)
   at System.Reflection.CustomAttribute.GetCustomAttributes(Assembly assembly, RuntimeType caType)
   at System.Reflection.Assembly.GetCustomAttributes(Type attributeType, Boolean inherit)
   at System.Attribute.GetCustomAttributes(Assembly element, Type attributeType, Boolean inherit)
   at MS.Internal.Xaml.MS.Impl.XamlSystemBinding.AddPairsFromAssembly(XamlSchemaContext schemaContext, Assembly asm, String uri, List`1 pairs)
   at MS.Internal.Xaml.MS.Impl.XamlSystemBinding.SearchForXamlNamespace(XamlSchemaContext schemaContext, String uriString, IEnumerable`1 referenceAssemblies)
   at MS.Internal.Xaml.XamlSchemaContext.GetXamlNamespace(String xmlns, Assembly localAssembly)
   at MS.Internal.Xaml.XamlSchemaContext.GetXamlNamespace(String xmlns)
   at MS.MarkupCompiler.ValidationPass.ValidateXaml(String fileName, Assembly[] assemblies, Assembly callingAssembly, TaskLoggingHelper log, Boolean shouldThrow)
   at Microsoft.Silverlight.Build.Tasks.ValidateXaml.XamlValidator.Execute(ITask task)
   at Microsoft.Silverlight.Build.Tasks.ValidateXaml.XamlValidator.Execute(ITask task)
   at Microsoft.Silverlight.Build.Tasks.ValidateXaml.Execute()
   at Microsoft.Build.BuildEngine.TaskEngine.ExecuteInstantiatedTask(EngineProxy engineProxy, ItemBucket bucket, TaskExecutionMode howToExecuteTask, ITask task, Boolean& taskResult)

[Vlad]

Hi Alex Wu,

 If this is Silverlight 4 you may need to try our Silverlight 4 assemblies.

Regards,
Vlad
the Telerik team

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