Operating System not found" when trying to use bootable USB flash drive on a fresh SSD. : r/windows
boot - No bootable device error after failed to install Ubuntu alongside Windows - Ask Ubuntu
Fix: Boot Device not Found Hard Disk - (3F0) Error on Ubuntu PC - Appuals.com
BACKUP YOUR CRAP: Missing Operating System, Backups, Disk Images, Home Servers, BootRec, BootMgr, RebuildBCD, FixBoot and Problems, Plural - Scott Hanselman's Blog
How to Fix Ubuntu Doesn't Boot After Installing in UEFI, No Bootable Device Ubuntu (Easy Tutorial) - YouTube
Missing Operating System - Windows 10 and Fedora 28 Dual Boot - Microsoft Community