BizTalk error messages are notoriously opaque. I decided to start recording my translations and solutions for these messages because... well because I keep encountering the same ones time and again, my mental buffer is full, and flipping through loads of notes is no longer fun. Error: Unexpected event ("document_start") in state "processing_empty_document". Scenario: This advice applies if you receive this error during receive pipeline xml disassembly processing, and you are using an envelope schema. ......