This chapter describes the file types used and generated by CFX-Solver. The CFX-Solver is run using an input file that is usually the CFX-Solver Input file (.def or .mdef) created by CFX-Pre. For most simulations, the CFX-Solver generates CFX-Solver Output (.out) and CFX-Solver Results (.res, .trn, .bak, .mres) files. Other files are also generated depending on the physical models used in the simulation, and how the simulation is run (that is, in serial or parallel).