Off-Topic seems goofier than usual lately, so I’m posting here. I think what I want to do is simple. Encrypt a bootable external HDD for off-site backup (mailed out of state). I use SuperDuper for cloning; I’ll buy CCC if that helps, but there are too many options there I don’t understand, for the time being. Outboard HDDs are always initialized and/or erased and set for Mac OS Extended (Journaled). Cloning works fine, but the seemingly simple function of selecting / encrypting via the Finder stalls out after the password is entered, with a popup that reads “A Recovery System for the targeted disk is required.” Installing a ‘recovery system’ seems to entail creating partitions and somehow installing OS. Which further seems to entail an arduous change the Target Disk, boot from the external, install OS (isn’t it there already from having backed up?). Is there a simple straightforward way to do this? FWIW, I’m stuck on 10.12.6 Sierra, so I can use old Adobe software. 2013 iMac. I don’t need to schedule automated backups. Before you reply, these conditions are set in stone (many reasons, don’t ask): No Time Machine No FileVault No Cloud No WiFi No Java I presume this has something to do with the need for a bootable backup, and my inexperience in encryption. I’ve never even put my clones to the test, frankly. Oddly, I did successfully encrypt a couple disks a few months back (via Finder), but I can’t remember what was on them. Any ideas? .