I have a Samsung T5 500GB external SSD that I use with my '12 27" iMac. I use Carbon Copy Cloner to clone the stock 1TB Fusion drive as a backup. I have a couple questions though.... 1. Why is it that even though I 'clone' the stock Fusion drive (APFS/Mojave 10.14.4) it still formats the T5 as Mac OS Extended (Journaled)? Do I need to reformat this manually in APFS first? When I bought it came as EX-FAT. 2. Why can't I get the Samsung T5 to show up as an option in the Startup Disk control panel? It starts up great off of it, but I have to hold down the 'option' key and manually select it.