If you receive error: COM object that has been separated from its underlying RCW cannot be used. The possible cause is invalid or malformed per instance configuration data. You most likely ran into bug (or undocumented feature) of BizTalk SDK. The problem won't show up until you edit value of component custom properties during deployment configuration. The reason is described below. When you create custom pipeline component with properties you will override ReadPropertyBag(Microsoft.B... ......