Thanks - was just doing a quick post in the midst of trouble shooting, should have tried more before posting. Got it all fixed! Had to uninstall the game via steam, restarted mac, redownloaded game, re-did the patch. And now I'm right as rain! Thanks to all for their help in coming up with these patches. You guys rock!
I am still on mac sierra, rocksmith auto-updated and then cldc wouldn't load. Just tried out the new patch, and same thing, the app is closing instantly