Error Messages

BOOTMGR Is Missing: How to Fix It Without Losing Your Files

Updated October 2, 2026 •6 min read

Your PC starts and shows a black screen: “BOOTMGR is missing. Press Ctrl+Alt+Del to restart.” Restarting brings you right back. It’s alarming, but in most cases your files are still sitting safely on the drive — the computer just can’t find the instructions to start Windows.

What BOOTMGR is

BOOTMGR (Windows Boot Manager) is a small program that loads Windows. It lives on the drive along with the Boot Configuration Data (BCD) that tells it where Windows is installed. If the computer can’t find or read BOOTMGR, it stops before Windows ever loads. A related message, “MBR is missing” or “Missing operating system,” points to the same family of problems.

Common causes

The wrong boot device — a USB stick, external drive, or disc is first in the boot order and has no Windows on it.
A corrupted boot sector or BCD, often after a power loss, failed update, or partitioning mishap.
A loose or disconnected drive cable (on desktops).
A failing hard drive that can no longer be read reliably.

Fixes, from simplest to strongest

1. Remove external media

Unplug USB drives, SD cards, and discs, then restart. This alone fixes a lot of BOOTMGR errors.

2. Check the boot order

Enter the BIOS/UEFI setup (usually F2, F10, F12, or Del at startup) and confirm the drive with Windows is first in the boot order. While you’re there, confirm the drive is detected at all. If it isn’t listed, skip ahead to “When the drive isn’t detected.”

3. Run Startup Repair

Boot from a Windows installation USB, choose your language, then Repair your computer → Troubleshoot → Startup Repair. Windows will try to rebuild the boot files automatically.

4. Rebuild the boot records manually

From the same menu, open Command Prompt and run:

bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd

(On some newer UEFI systems, bootrec /fixboot may report “Access is denied”; Startup Repair or bcdboot C:\Windows is the alternative.)

These commands rewrite boot information — they don’t touch your documents or photos.

The move that can wipe your files: reinstalling Windows

If repairs fail, it’s tempting to reinstall Windows. Don’t choose “Custom: install Windows only” and format or delete partitions if your files aren’t backed up — that erases everything on the drive.

Instead, rescue your files first:

Remove the drive and connect it to another computer with a USB adapter or enclosure, then copy your files off. (If it’s BitLocker-encrypted, you’ll need the recovery key.)
Or boot from a Linux live USB and copy files to an external drive.

Only reinstall once your data is safe.

When the drive isn’t detected

If the BIOS doesn’t list the drive, or the drive clicks, beeps, or buzzes, BOOTMGR isn’t the real problem — the drive is failing. Boot repairs won’t help, and repeated restarts can make things worse. Power it down. That’s a hardware recovery job.

The bottom line

“BOOTMGR is missing” is usually a boot-configuration problem: remove external media, fix the boot order, and run Startup Repair or bootrec. Your files are typically untouched — just don’t reinstall Windows over them. If the drive isn’t detected or makes noise, it’s a hardware failure.

If the drive has failed, our desktop & PC data recovery service recovers it for one flat price, with no charge unless we get your data back.