If there are multiple drives installed in the computer, then it can create confusion as to which drive has a Bootloader. This scenario usually happens when Master Boot Record is on the wrong drive.

Unless your computer is pretty old, it probably uses UEFI (Unified Extensible Firmware Interface) to boot. The idea is that a bootloader picks up files from an EFI partition and uses them to start ...

When a VirtualBox virtual machine boots directly into the UEFI Interactive Shell, it’s typically because the EFI firmware cannot automatically find a bootable operating system loader. This could be ...