Running ArcGIS 10.5 with 10.5 ArcHydro. Everything is working fine with the various GP tools until I get to time of concentration in H&H Modeling. Running the tool on my dataset generates the Error 010043 "All selected cells are at absolute barrier." at the step where it creates the maximum length flow path. It stops when creating the flow path points. The tool creates the Tc roaster just fine. I made sure that all of the slopes are non-0 and the longest flow path tool works fine in the Terrain Preprocessing GP tools. I tried running the tool on the GP tutorial dataset and it ran for about 18 hours at the same step of creating the longest flow path and never finished. If you can tell me how the Tc tool finishes the calculations, I can probably finish the process manually. Thanks.