Hi TUFLOW FV, I am trying to initialise a TUFLOW FV model. Once FV reads the mesh elevation levels the following error message is displayed and the model shuts down. ERROR: Duplicate grid labels are not permitted. A screenshot is shown below. The model previously ran through to completion although this iteration of the model includes an additional nested wave model and some changes to the BC's. It seems strange it would produce an error after reading the mesh elevations. Cheers