Hi Ayman,
Thank you for sending the file. It does not contain a Generic System case, so I was not able to test it with the Combine Cases macro.
However, I did see the message about the mass flow rate for the "CSP 10" case. Because it is not a critical problem, SAM displays the message on the "Notices" tab of the results page but does not display it as a simulation message.
The message says that the calculated design mass flow rate is about 1.8 times greater than the value specified in the inputs. You could resolve this by changing the value of the maximum design mass flow rate on the Solar Field page from 12 kg/s to 22 kg/s. That may result in pipes with unrealistically large diameters, so you may need to adjust some other parameters. If the purpose of your analysis is to estimate the output of a trough plant and you are not concerned with design details, you could ignore the message.
Best regards,
Paul.