Pipe line tracing understanding

Hi All,

My environment facing a kind of weird issue, I would say.

My environment is undergoing a migration from Groupwise 6.5.7 to Exchange 2013.

mail flow from GroupWise is forwarded (flat forwarding enable) to Exchange 2013. Been noticing there are blank emails being forwarded to Exchange.

By turning on the pipe line tracing in Mailbox server, I can see there are the blank email info.

Inside the pipe line tracing email folder, there is Original, Routing & SMTP log.

Wanted to know how this 3 log files is created to further troubleshoot the blank email problem. Anyone have the idea how it works? Some of the log doesn't have Original, or Routing as example.

Thanks and Regards,

Low