Before running a UTCHEM simulation, the UTCHEM simulation must be saved using the Save or Save As commands.
GMS saves three files:
*.utc contains the actual UTCHEM input information. This file can be read separately by GMS.
*.uts is the UTCHEM super file and is only read by GMS. When you choose the Open command from the File menu, a *.uts file extension is one of the Model Super File filters.
*.hdd is the UTCHEM head file. UTCHEM needs this file for memory management. If you only have a UTCHEM input file, you can read the simulation into GMS and resave it. GMS will then create the appropriate *.hdd file.
Related Links:
Running UTCHEM
New Simulation
Reading a UTCHEM Simulation
Delete Simulation