This issue can be found when using a MIDI device or another application that requires you to use OMS. It is commonly found with Reason and/or Midiman midi hardware (keyboards and interfaces).
Unfortunately, there isn't much of a solution to this problem. It has to do with using applications and hardware that depend on OMS. The good news is that you can work around the problem by being sure to Save and Close your DP project BEFORE you attempt to Quit DP. It is also recommended that other applications running be QUIT before quitting DP. In most cases, DP runs fine aside from this particular issue.
It is anticipated that the obsoletion of OMS when OSX is fully supported by DP and other music applications will rid users of this problem.