Symptoms
When you develop an application by using Microsoft Lync Server 2010 Group Chat SDK APIs, the application crashes intermittently. Additionally, the following exception is generated:
Exception Type: System.InvalidOperationExceptionException message: You can set a result only onceException Source: Microsoft.Rtc.Collaboration.GroupChatException stacktrace:at Microsoft.Rtc.Collaboration.GroupChat.Internal.AsyncResultNoResult.SetAsCompleted(Exception exception, Boolean completedSynchronously)at Microsoft.Rtc.Collaboration.GroupChat.Internal.MessageRouter.AddPendingMessageHelper(IAsyncResult asyncSend)at Microsoft.Rtc.Collaboration.GroupChat.Internal.AsyncResultNoResult.SetAsCompleted(Exception exception, Boolean completedSynchronously)at Microsoft.Rtc.Collaboration.GroupChat.Internal.WrappedSignalingSession.SendInfoHelper(IAsyncResult ucmaResult)at Microsoft.Rtc.Signaling.CompletionCallbackWorkItem.Microsoft.Rtc.Signaling.IWorkitem.Process()at Microsoft.Rtc.Signaling.WorkitemQueue.ProcessItems()at Microsoft.Rtc.Signaling.SerializationQueue`1.ResumeProcessing()at Microsoft.Rtc.Signaling.SerializationQueue`1.ResumeProcessingCallback(Object state)at Microsoft.Rtc.Signaling.QueueWorkItemState.ExecuteWrappedMethod(WaitCallback method, Object state)at System.Threading.ExecutionContext.runTryCode(Object userData)at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)at System.Threading._ThreadPoolWaitCallback.PerformWaitCallbackInternal(_ThreadPoolWaitCallback tpWaitCallBack)at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback(Object state)
Cause
This issue occurs because a function that can be called by all APIs is unexpectedly called two times.
Resolution
To resolve this issue, install the following cumulative update:
2709419 Description of Lync 2010 Group Chat SDK: June 2012
