I have Mountain Lion running on a 2012 MBP 9.2 Apple keeps prompting me to upgrade to a free version of El Capitan. I'm torn about what to do... On one hand, I don't want to change anything on my old MBP, because things work fine now. On the other hand, there is an important piece of software that I need for work that will not run on Mountain Lion. I am looking into getting another MBP, but in the mean time I don't want to trash what I have. BTW, I do use CCC weekly, so I guess that would provide a back. Any advice on this?