title: .Net Serialization Exception error with .net 3.5 WCF application hosted in IIS with parallel extension System.Threading dll
body: <p>I am getting following error when there is load on my .net 3.5 WCF application hosted in IIS with </p>
  
  <p>An unhandled exception occurred and the process was terminated.</p>
  
  <p>Application ID: DefaultDomain</p>
  
  <p>Process ID: 9008</p>
  
  <p>Exception: System.Runtime.Serialization.SerializationException</p>
  
  <p>Message: Unable to find assembly 'System.Threading, Version=1.0.2856.102, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.</p>
  
  <pre><code>StackTrace:    at System.Runtime.Serialization.Formatters.Binary.BinaryAssemblyInfo.GetAssembly()
     at System.Runtime.Serialization.Formatters.Binary.ObjectReader.GetType(BinaryAssemblyInfo assemblyInfo, String name)
     at System.Runtime.Serialization.Formatters.Binary.ObjectMap..ctor(String objectName, String[] memberNames, BinaryTypeEnum[] binaryTypeEnumA, Object[] typeInformationA, Int32[] memberAssemIds, ObjectReader objectReader, Int32 objectId, BinaryAssemblyInfo assemblyInfo, SizedArray assemIdToAssemblyTable)
     at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryObjectWithMapTyped record)
     at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run()
     at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
     at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
     at System.Runtime.Remoting.Channels.CrossAppDomainSerializer.DeserializeObject(MemoryStream stm)
     at System.AppDomain.Deserialize(Byte[] blob)
     at System.AppDomain.UnmarshalObject(Byte[] blob)
  </code></pre>