Starting with Fluent 18.2, the serial version has been revised and uses the same processes as the parallel version. This makes the behaviour more consistent between the serial and parallel versions. For the serial version of Fluent 18.2 under Windows six processes start: 1x cx1820.exe 1x fl_mpi1820.exe 1x fl1820.exe 1x fluent.exe 1x mpid.exe 1x mpirun.exe For the serial version of Fluent 18.2 under Linux 9 processes start: 3x fluent 1x cortex.18.2.0 1x fluent.18.2.0 1x mpirun.fl 1x mpirun 1x mpid 1x fluent_mpi.18.2