I have two MacBook Pros - one with Mountain Lion and one with Sierra. And on a regular basis, I run CCC and clone each laptop to a separate HDD. Because the name of each drive reflects the computer and the date (e.g. Retina_2019-07-21), I have a need to update the drive name before each clone. In Sierra, I just go to Disk Utilities, right-click on the drive, and update it from say "Retina_2019-06-15" to "Retina_2019-07-21". In Mountain Lion, this is not possible when FileVault is turned on. However in an earlier thread someone showed me that you can go into Finder and simply rename the drive there. Of course the downside to this approach is that in Disk Utilities you then have two names. For example, it appears that the physical drive retains it's original name (e.g. "MBP_2019-04-01") but that there is a new logical drive called the enwer name (e.g. "MBP_2019-04-30") So the only way to get the Mountain Lion drive's name updated would be to DE-crypt the entire HDD, then rename it in Mountain Lion Disk Utilities, and then RE-encrypt it - which could take days to do?! I am looking for a better approach to this! So on to my questions... 1.) Will I break anything if I encrypt an external HDD using Mountain Lion and then I try to unlock it while it is plugged into Sierra? 2.) Can I take an external HDD encrypted in Mountain Lion and decrypt/re-eencrypt it in Sierra? 3.) If I take an external HDD encrypted using Mountain Lion, plug it into my laptop running Sierra, unlock it in Sierra, and then change the drive name using Sierra's Disk Utility, what will happen when I plug it back into my laptop running Mountain Lion? To summarize, it seems pretty easy to take an external FileVault HDD and rename it using Sierra's Disk Utility, but I don't want to FUBAR the encryption on that Mountain Lion drive!! I gues I do not understand how FileVault and encryption work on my old laptop running Mountain Lion and then on my newer Retina running Sierra... Someday I will get my old MacBook updated to a more modern OS, but there is still software that I use on a weekly basic that will NOT run on my Retina with Sieera, so I keep nursing my old Mountain Lion laptop along until I can get things working on a newer machine. Hope my questions and concerns make some sense?!