This just happened to me. I was super careful to select the correct drive as I had two USB drives plugged in (one with the installer, one the target of the install) on my Mac. Ubuntu was installed on the correct USB, but the boot loader went on the Mac. I can still boot into macOS by holding down Opt, but I can't boot off the USB stick on other machines because there's no boot loader.
Red, you posted your solution from a different account (tim-richardson), confused me at first. David -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1396379 Title: installer uses first EFI system partition found even when directed otherwise To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1396379/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs