Getting “An operating system not found” error? When I tried dual booting Ubuntu 14.04 LTS from a bootable USB stick with my Windows 10 I received it too, nothing seemed to work for me. Here, I will list down the possible steps you can follow and see if it works for you.
- If you’re trying to boot from an external HDD connected via USB, it might be a reason for failure; try a bootable pendrive instead.
- Try removing all other USB devices/cables and keep only the pendrive intact and try reading the OS from pendrive during startup (Press F12 for Boot options on Dell systems).
- Most of the times the pendrive isn’t formatted and made bootable correctly; try using windows command line to make your USB bootable effectively: Create a bootable USB Flash Drive [Note: In step 9 in the link, select format filesystem as FAT32 not NTFS even if your platform is BIOS and not UEFI]. Or,
- Prepare USB stick exactly as described in Ubuntu documentation: How to create a bootable USB stick on Windows. Instead of using USB installer software suggested on the Ubuntu site you can use Rufus, it comes highly recommended for creating bootable sticks.
- Make sure you format your pendrive as FAT32, not NTFS and try making it bootable then.
Point 5 worked for me. My bootable USB stick was in NTFS format, after formatting it to FAT32, Ubuntu ran like a cake.