Major problem of color calibration since months , need help.

Hi friends , my monitor is samsung SA300 , I have been editing on it since 10 years now , I have two OS on two separate hard discs that use the same monitor, on one I have mountain lion and on another I have Sierra , both have fcpx , have the same ICC profile / colour profile selected on both the systems and the monitor settings remain the same .... but I don't know why colours on both the OS are completely different , with mountain lion I get colour close to perfect but on sierra everything is unreal and misleading , I have calibrated both the monitor with the inbuilt software too, both have same icc profile , in both monitor setting remains same .... but since I do not see anything else on the OS with which I can manipulate colour , brightness and contrast , I have not been able to understand how to get colours on sierra close to real or at least like on my mountain lion , what can be the possible reason of this difference and what can I do to assure similar colors on sierra too... plz help.