Windows & BSOD · critical

How to fixBOOTMGR-MISSING

BOOTMGR is missing

What this error means

BOOTMGR is missing (BOOTMGR-MISSING) is a critical-severity fault affecting the Windows operating system. The 'BOOTMGR is missing' error appears at startup before Windows loads. The Windows Boot Manager (BOOTMGR) is the first program loaded by UEFI/BIOS to find and launch the Windows OS loader. If BOOTMGR is missing, corrupted, or on a partition that is not marked as active/bootable, Windows cannot start at all. The steps below are ordered to resolve this efficiently.

Before you begin

Save open work and back up important files. Use instructions for your exact device and software version. If Windows cannot start, see the startup guide.

Work through these checks

0 of 3 complete
01Boot from Windows installation USB and run Startup Repair
  1. Boot from Windows installation USB and run Startup Repair
What to expect

Check whether the original symptom still occurs.

If it does not help

Continue only if this check applies to your device. Consult its manufacturer if you are unsure.

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02Use bootrec /fixmbr and bootrec /fixboot
  1. Use bootrec /fixmbr and bootrec /fixboot
What to expect

Check whether the original symptom still occurs.

If it does not help

Continue only if this check applies to your device. Consult its manufacturer if you are unsure.

Browse related errors
03Verify boot drive is properly connected and detected in BIOS
  1. Verify boot drive is properly connected and detected in BIOS
What to expect

Check whether the original symptom still occurs.

If it does not help

Continue only if this check applies to your device. Consult its manufacturer if you are unsure.

Browse related errors

Possible causes

  • Corrupt MBR or Boot Sector
  • Bootable partition not marked active
  • Drive disconnected during boot