i just sold an old iMac and bought a 2017 15” MacBook Pro. This is my first machine with USB-c. I used migration assistant to move my data from the iMac to the new laptop over a thunderbolt to USB-c adapter. I also have a 2014 15” MacBook Pro. It has been my habit to keep my macs as clones of each other. So yesterday I tried to clone my new 2017 MBP to my old 2014 MBP. I have the appropriate cable and i know the cable and adapter are fine. I first tried a Smart Update, which resulted in a system that would boot but not let me login. Then I did an erase of the old system and full clone of the 2017 MBP to the 2014MPB. This time, the 2014 won’t even boot. I’ve been Cloning macs for over a decade without. A problem, and it never mattered what model they were. iMacs to MacBooks, old Mac Pro to MacBook Pro, it has never failed as long as the OS was the most recent, and that the older machine was known to be able to handle the newer machine’s OS. It always worked. Is there something very different about the new Macs, or the version of Sierra that they come with, that prevents that copy of the OS from running on a 2014 Mac? Should I try Carbon Copy Cloner, or is this problem inherent to the hardware combination? --- Post Merged, Sep 23, 2017 --- I messed up the thread title. As I wrote in the post, I am trying to clone a USB-c Mac to a pre-USB-c Mac. Cloning from the 2017 to the 2014. After the clone complete and I try to boot the 2014, it immediately fails with a black screen with a bunch of Unix error messages.