Hi all. Recently LR 6 "quit unexpectedly " on my iMac after importing images from my iPhone (It would open then immediately quit). I have restored LR 6 from an earlier backup, but I now wish to upgrade from LR 6.14, presently on Sierra 10.12.6, to a current plan, probably Classic, and a suitable mac OS. I'm not sure of the best sequence of actions, or what is the best Mac OS. Any suggestions would be much appreciated.