Hi
I'm using a MBP Mid-15 with OSX 11.5 and the latest SD!
I want to upgrade my SSD and need to boot from an external drive to do so. I formated my Toshiba USB3-Drive as APFS and did a full back up (Backup All files. I actually did that twice now, but the drive won't show up as a bootable device. Neither when I hit Option-Key on startup nor when I check the startup-pane in preferences.
