WindowsBootManager

Windows Boot Manager, also known as bootmgr, is a small piece of software that loads when a Windows computer starts up. It is responsible for managing the boot process for Windows operating systems starting from Windows Vista. Before Windows Vista, the boot loader was part of the operating system kernel itself. Windows Boot Manager is located in the system partition, which is usually a hidden partition that contains boot files.

When a computer is powered on, the BIOS or UEFI firmware initializes hardware and then looks for a bootable device. Once a bootable device is found, it loads the boot manager. The boot manager then reads its configuration data, which is stored in the Boot Configuration Data (BCD) store. The BCD store contains information about all installed operating systems, including their locations and boot options.

If multiple operating systems are installed on the computer, the Windows Boot Manager will present a menu allowing the user to choose which operating system to start. If only one operating system is installed, it will proceed to load that operating system directly. The boot manager also handles various boot options such as safe mode, last known good configuration, and debugging. It plays a crucial role in ensuring a smooth and efficient startup for Windows.