Thanks!

After un-checking the "enable conversion error checking" box at time of efile, I was able to efile a MD return which was accepted.  I got that tip from this community.  I would never have known it had any impact.  Regardless, there is a problem somewhere that has yet to be addressed by MD and/or Intuit.  Until it is resolved, I will use the workaround and hope that other returns can also be successfully efiled.

Thanks again.

Mike