Symptoms
In Microsoft BizTalk Server, multiple instances of the same message are dropped in the receive location. If the messages are processed at the same time, an error that resembles the following may be logged in the Application log:
A message sent to adapter "FILE" on send port "SendPortName" with URI "URI" is suspended.
Error details: There was a failure executing the send pipeline: "Microsoft.BizTalk.DefaultPipelines.XMLTransmit, Microsoft.BizTalk.DefaultPipelines, Version=3.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" Source: "XML assembler" Send Port: " SendPortName" URI: "URI" Reason: Type ‘TypeName’ is not declared.
Cause
The issue occurs because multiple threads try to change the same object when they process multiple requests at the same time.
Resolution
Cumulative update information
The fix that resolves this issue is included in Cumulative Update 2 for BizTalk Server 2013 R2.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the service pack and cumulative update list for BizTalk Server.
Learn about BizTalk Server hotfixes and cumulative update support.