The BOOTMGR is missing error appears as white text on a black screen right after you power on, before Windows loads. BOOTMGR (the Windows Boot Manager) is the small program that starts Windows; when the PC can’t find it, nothing loads. Causes include a corrupted boot sector, a wrong boot order in BIOS, an incorrectly marked active partition, or a failed update.
The symptom
A black screen with one of: “BOOTMGR is missing. Press Ctrl+Alt+Del to restart”, “Couldn’t find BOOTMGR”, or “BOOTMGR is compressed.” Pressing the keys just restarts to the same message.
Fix 1 — Check the BIOS boot order
Often the PC is simply trying to boot the wrong device. Enter BIOS/UEFI (Del, F2 or F10), remove any USB drives or SD cards, and make sure your Windows disk is first in the boot order.
Fix 2 — Run Startup Repair
Boot into the Windows Recovery Environment (force three failed boots, or use a recovery USB) and choose Troubleshoot › Advanced options › Startup Repair. This rewrites the boot manager automatically in many cases.
Fix 3 — Rebuild the boot files from Command Prompt
If Startup Repair doesn’t fix it, open Command Prompt from Advanced options and run:
bootrec /fixmbrbootrec /fixbootbootrec /rebuildbcd
If /fixboot returns “Access is denied” on a UEFI system, rebuild the EFI boot files with bcdboot C:\Windows /s S: /f UEFI (where S: is the EFI system partition you assign with diskpart).
Fix 4 — Mark the correct partition active (MBR/legacy)
On older BIOS/MBR systems, run diskpart, then list disk → select disk 0 → list partition → select partition 1 (the small System Reserved one) → active. This tells the PC which partition to boot from.
Fix 5 — Boot from a recovery USB
All of the above require a working recovery environment. If Windows can’t provide one, a bootable recovery USB gives you Startup Repair and a command prompt from the outside, so you can rebuild BOOTMGR even on a PC that shows nothing but the error.
How our RecoveryUSB handles this
Boot the PC from our RecoveryUSB and you get the full repair toolkit — guided Startup Repair, bootrec, bcdboot and diskpart — without needing Windows to cooperate. The included guide shows the exact commands for both UEFI and legacy systems.
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Shop Recovery USBsFrequently asked questions
What does “BOOTMGR is missing” mean?
The Windows Boot Manager file that starts Windows is missing, corrupted, or on a partition the PC isn't trying to boot from. Windows can't load until it's restored.
How do I fix BOOTMGR is missing without a Windows disc?
Use the built-in recovery environment (force three failed boots) to run Startup Repair or bootrec commands. If that environment is unavailable, boot from a recovery USB to get the same tools.
Does fixing BOOTMGR delete my files?
No. Repairing or rebuilding the boot manager only touches boot files, not your personal data.