I have an external USB drive, and used Carbon Copy Cloner to make a copy of my internal SSD. However, when I reboot and hold down the option key, the external drive does not appear as a choice (only my main drive and boot camp partition). I recall this working on my old MacBook Air. Has anyone run into issues either with CCC or the 2011 MacBook Air in this regard? I'd like to set up the external drive to use for testing/beta purposes. It is formatted HFS+ and has the GUID partition table. I also created a restore partition on the external drive using CCC.