Cause

There is more than one graphical placement of a planning object in the representation type <x> on one or several pre-planning pages of your project.

Solution

1. Locate the planning object placed graphically multiple times by using the Go to (graphic) functionality from the popup menu in the Message management dialog.
2. Delete the excess graphical placement.
3. Repeat the deletion process for any further excess placements.
4. Then start a new check run.