In addition, you may receive different messages like ' BOOTMGR is missing. Press Ctrl+Alt+Del to restart', as shown below: And you can see the message ' BOOTMGR is missing. When the BOOTMGR error message occurs, the Windows has initially started to load. This issue usually appears shortly after the computer is turned on, immediately after the Power On Self Test (POST for short) is complete.
However, sometimes BOOTMGR may be missing or lost due to reasons including incorrect bootable disk, damaged MBR, outdated BIOS, loose or damaged hard disk interface cables, etc. BOOTMGR can read boot configuration data and display the operating system selection menu. If there is no system reserved partition, BOOTMGR probably locates in your primary partition C. On most PCs, the partition is labeled as system reserved without a drive letter. Usually, the BOOTMGR file is read-only and is locating in the boot directory of the partition which is set as 'active'.
