Cause

A PCT loop or PCT loop function exists more than once with the same identifying designation according to the settings under Options > Settings > Projects > "Project name" > Pre-planning > Numbering / PCT loops in the project.

Solution

1. Locate the PCT loop or PCT loop function designated in identical fashion multiple times according to the settings in the pre-planning navigator using the Synchronize selection function offered by the popup menu in the Message management dialog.
2. Call the Properties <...> dialog of the PCT loop or PCT loop function, and depending on the selected basic segment definition, bring to the front the Loop, Measuring function, or Consumer function tab.
3. Modify the Number property on the PCT loop or PCT loop function, or modify the settings in the Identifying properties in addition to the 'Number' group box below the menu items Options > Settings > Projects > "Project name" > Pre-planning > Numbering / PCT loops.
4. Then start a new check run.