"Attempting to load an assembly with an invalid signature" error using AFSdk

Discussion created by VarbanVarbanov on Jan 16, 2014
Latest reply on Jan 21, 2014 by VarbanVarbanov

Hi, I have a following problem

I'm using the following method from AFSdk called within a WCF service method:

var server = PIServer.FindPIServer(_connection.PISystem, piServerName);

 It works in the development environment and it seems that it worked in production until recently

Now there is a following exception (written in event log) occured: " Attempting to load an assembly with an invalid signature.". The callstack is below it suggests that the problem is in "FindPiServerMethod":


Error: System.ServiceModel.FaultException`1[System.ServiceModel.ExceptionDetail]: Attempting to load an assembly with an invalid signature. (Fault Detail is equal to An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is:
System.IO.FileLoadException: Attempting to load an assembly with an invalid signature.
at OSIsoft.AF.PI.PIServersGlobal.get_DirectoryProvider()
at OSIsoft.AF.PI.PIServersGlobal.get_PIDirectoryProvider()
at OSIsoft.AF.PI.PIServersGlobal.Load(Boolean force)
at OSIsoft.AF.PISystemsGlobal.get_PIServers()
at OSIsoft.AF.PI.PIServer.FindPIServer(PISystem system, String name)
at AssetsProvider.Service.AssetsEditor.AddUpdatePIPoints(List`1 piPoints, String piServerName)
at SyncInvokeAddUpdatePIPoints(Object , Object[] , Object[] )
at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessM...).


The service is using constantly (not ever changed since it is created) version of AFSDK -  v4.0.30319.  
There are no errors in Pi Server Log and also in AF log

Any quick suggestions about why this happens and how to solve it will be highly appreciated!

Thank you in advance!