I first ran into this problem 2 years ago, migrating a natural convection problem for a camera from Solidworks Flow Simulation 2015 to Solidworks Flow Simulation 2017. The simulation gave 2 very different results when the old files were automatically updated to the newer version(on 2 different machines). I never figured it out why, but just gave up and stuck working with the older model on 2015.
I am now again running another old v2015 cold-plate model from a collage in my machine v2017, again with nothing changed. I am getting some very different results that he had reported. An additional problem was that the Goals that were set, had now disappeared from the selection menu, but it's still there when I ran the case.
Anyone ran into this problem? or any sort of solution? Thanks.