.Net Serialization Exception error with .net 3.5 WCF application hosted in IIS with parallel extension System.Threading dll

Question

I am getting following error when there is load on my .net 3.5 WCF application hosted in IIS with

An unhandled exception occurred and the process was terminated.

Application ID: DefaultDomain

Process ID: 9008

Exception: System.Runtime.Serialization.SerializationException

Message: Unable to find assembly 'System.Threading, Version=1.0.2856.102, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.

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)

Answer 1

It was due to some unhandled exception. Basically my application doing communication to another WCF service in a background thread. service request were getting timeout and throwing exception. So just have put try catch around the call. After that worker process stop crashing