DjznBR: Your issue may be caused by allowing the PC to boot the installer image using Legacy/BIOS mode, rather than its native UEFI mode.
ISO Desktop images are hybrid; that is they are configured to boot in any of three different modes: 1. In UEFI mode using the Simple Boot Path (EFI/BOOT/BOOTX64.EFI) with GPT and an EFI System Partition (bootable as optical media or removable mass storage) 2. In BIOS mode using the hybrid/protective MBR containing the isolinux boot-strap and isolinux.bin 3. As pure ISO9660 media using the BIOS El Torito boot specification for CD/DVD media These combinations allow the device to boot as removable optical media or removable mass storage on BIOS and UEFI systems. If you experienced the "Missing operating system" message the UEFI PC tried to boot the image using Legacy BIOS/Compatibility Support Module mode. You'll not see that message when booting in UEFI mode. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/277903 Title: Missing Operating System [message at boot] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-cdimage/+bug/277903/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
