I have two WCF services hosted in a single Windows Service on a Windows Server 2003 machine. If the Windows service needs to access either of the WCF services (like when a timed event occurs), it uses one of the five named pipe endpoints exposed (different service contracts). The service also exposes HTTP MetadataExchange endpoints for each of the two services, and net.tcp endpoints for consumers external to the server. Usually things work great, but every once in a while I get an error message that looks something like this: System.ServiceModel.EndpointNotFoundException: There was no endpoint listening at net.pipe://localhost/IPDailyProcessing that could accept the message. This is often caused by an incorrect address or SOAP action. See InnerException, if present, for more details. --- System.IO.PipeException: The pipe endpoint 'net.pipe://localhost/IPDailyProcessing' could not be found on your local machine. --- End of inner exception stack trace --- Server stack trace: at System.ServiceModel.Channels.PipeConnectionInitiator.GetPipeName(Uri uri) at System.ServiceModel.Channels.NamedPipeConnectionPoolRegistry.NamedPipeConnectionPool.GetPoolKey(EndpointAddress address, Uri via) at System.ServiceModel.Channels.ConnectionPoolHelper.EstablishConnection(TimeSpan timeout) at System.ServiceModel.Channels.ClientFramingDuplexSessionChannel.OnOpen(TimeSpan timeout) at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.OnOpen(TimeSpan timeout) at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.CallOpenOnce.System.ServiceModel.Channels.ServiceChannel.ICallOnce.Call(ServiceChannel channel, TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.CallOnceManager.CallOnce(TimeSpan timeout, CallOnceManager cascade) at System.ServiceModel.Channels.ServiceChannel.EnsureOpened(TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs) at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation) at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message) It doesn't happen reliably, which is maddening because I can't repeat it when I want to. In my windows service I also have some timed events and some file listeners, but these are fairly infrequent events. Does anyone have any ideas why I might be encountering an issue? Any help would be greatly appreciated.