Outbound ticket has been created.  Thanks Antony.

Hello Antony, just wanted to provide an update on the issues with PST imports.  We were able to import millions of different emails from various PST files.  In doing so we were able to resolve many different issues that were causing import problems.  I would recommend that you update to the latest SmarterMail server release and then try the import process again.  

Thank you for this update and work on this.  We already upgraded to 7417 and will let you know if any other PST imports prove problematic.