Fix BOOTMGR is Missing Error

Contents

1. Symptoms of the problem

When computer is powered up, an error message "BOOTMGR is missing
Press Ctrl+Alt+Del to restart" appears (white-on-black letters in text mode and blinking cursor):

Boot Problem - BOOTMGR is missing

2. Normal boot sequence

The rest of this article refers to Windows 7, but all information below applies to Windows Vista and Windows 8 as well.

Normally Windows 7 boots as shown below:

Normal boot sequence of Windows 7
  1. BIOS loads 1st sector from HDD (Master Boot Record), verifies 55 AA signature and transfers control to Master Boot Record.
  2. Master Boot Record scans partition table for active partition, then it loads 1st sector from active partition, verifies 55 AA signature, and transfers control to Boot Sector.
  3. Boot Sector loads 15 additional sectors from the beginning of disk (Volume Boot Record) and transfers control to first additional sector of VBR.
  4. Volume Boot Record loads BOOTMGR file from root directory of boot partition into the memory and transfers control to it.
  5. BOOTMGR loads Boot\BCD registry hive and displays boot menu. BOOTMGR is able to run memory test and set safe mode boot flag per explicit user request. But normally, it loads winload.exe when computer boots normally (cold startup) or winresume.exe (when computer resumes from hibernation).
  6. Winload.exe opens SYSTEM registry hive, gets list of drivers, loads NTOSKRNL.exe, loads drivers (*.SYS files) and transfers control to NTOSKRNL.exe.
  7. Winresume.exe loads memory dump from hiberfil.sys and transfers control to it.

3. Defect in the boot sequence which leads to BOOTMGR is missing error

Defect in the boot sequence which is a reason for 'BOOTMGR is missing' error is shown below:

Reason for BOOTMGR is missing error
  1. BIOS loads 1st sector from HDD (Master Boot Record), verifies 55 AA signature and transfers control to Master Boot Record.
  2. Master Boot Record scans partition table for active partition. There is one active partition, so Master Boot Record loads 1st sector from active partition (Boot Sector), and transfers control to it.
  3. Boot Sector loads the rest of Volume Boot Record and VBR tries to find BOOTMGR at the root directory of boot partition but fails because "BOOTMGR" file does not exist or not readable.
  4. The rest of usual boot events does not happen.

4. How to fix BOOTMGR is missing error

1) Download EBCD and burn it to CD/DVD according to the instructions, then set up your BIOS to boot from CD. You need full EBCD version to actually write changes to the disk, but it's recommended to try demo version first to make sure  there are no hardware incompatibilities.

2) Boot EBCD:

Fix BOOTMGR is missing with EBCD - Main Menu

3) Run File Manager from the main menu:

Fix BOOTMGR is missing with EBCD - File Manager Started

4) Press Alt+F1 and choose your boot partition from the menu. In Windows 7 and Windows 8 boot partition has size about 100MB in size and "System Reserved" volume label. In Windows Vista separate boot partition does not exist, computer boots from system disk where Windows OS files are installed (use UP and DOWN arrow keys and ENTER to navigate the menu):

Fix BOOTMGR is missing with EBCD - Choosing Windows 7 boot partition

5) In this example, BOOTMGR file is missing from boot partition. If it exists in your environment, delete it (set cursor to the file using arrow keys UP and DOWN and then press F8). If BOOTMGR file is not deleteable, then rename it (for example, to BOOTMGR.OLD by pressing F6 key):

Fix BOOTMGR is missing with EBCD - Checking non-existence of BOOTMGR file

6) Insert Windows 7 installation CD to your CD/DVD drive and press Alt+F2. Choose your CD/DVD drive from the menu using UP and DOWN arrow keys:

Fix BOOTMGR is missing with EBCD - Choosing Windows XP installation disk

7) Press ENTER:

Fix BOOTMGR is missing with EBCD - Reading Windows XP installation disk

8) Press TAB key to switch input focus to the right panel and navigate to the BOOTMGR file:

Fix BOOTMGR is missing with EBCD - Navigating to BOOTMGR file

9) Press F5 to copy BOOTMGR to the left panel. Confirm with ENTER key:

Fix BOOTMGR is missing with EBCD - Restoring BOOTMGR on the system disk

10) BOOTMGR should appear on the left panel. Make sure it is there and press F10, ENTER to exit EBCD File Manager:

Fix BOOTMGR is missing with EBCD - Verifying BOOTMGR is restored on the system disk

11) Choose Mount & Boot Center in the main menu:

Fix BOOTMGR is missing with EBCD - Running Mount and Boot Center from EBCD main menu

12) Wait:

Fix BOOTMGR is missing with EBCD - Waiting for Mount and Boot center to initialize

13) Please make sure that radio button "called by BIOS" is selected for your the bootloader of your main OS. Then click the OK button:

Fix BOOTMGR is missing with EBCD - Verifying BOOTMGR is called by BIOS

14) "BOOTMGR is missing" boot problem should be fixed now. Choose 'Reboot' in the EBCD main menu:

Fix BOOTMGR is missing with EBCD - BOOTMGR is missing problem is fixed, rebooting

Please note: Mount & Boot Center verifies entire boot path from BIOS to the OS boot loader, so other boot problems may be automatically fixed at this point.