Recently we have been receiving another series of complaints from clients that had trouble reading the pdf attachment of a BizTalk dynamic generated email. For some years we have been using the MIME encoder pipeline component and dynamically buildup our emails as multi-part message from inside orchestration. We got the mustard from here. As said, it wasn't the first time we had these complaints. But it was always for a small minority of users only. Hence it sounded more like a user-specific issue. ......