MFX requires an “ANSYS Mechanical” or higher license and any CFX/CFD-Flo license, a single “ANSYS Multiphysics” license, or a single “ANSYS Mechanical CFD-Flo” license for the duration of the calculation. For legacy licenses, System Coupling requires an “ANSYS Structural” or higher license and any CFX/CFD-Flo license for the duration of the calculation. For current licenses, System Coupling requires an “ANSYS Mechanical Enterprise” license and any Fluent/CFX/CFD-Flo license for the duration of the calculation. The most cost effective way to conduct a 2-way FSI analysis is to use the “ANSYS Mechanical CFD”, which allows you to perform the 2-way analysis using this single license. When not performing an FSI analysis, only one solver can be run at a time using this license. There is a defect in version 18.0 and earlier whereby when using multiple licenses for a system coupling analysis (e.g. Mechanical Enterprise + Multiphysics), the license preferences for license sharing must be set to allow for license sharing. Otherwise, CFX-Pre may call for the license before Meshing has released it, resulting in the following error: “Error opening CFX Setup case file. License check out failed.” This defect has been fixed in version 18.1.