Fix Bootmgr Is Missing Error in Windows 10

This guide walks you through fixing the “Bootmgr is missing” error in Windows 10, which prevents your PC from starting normally. The fix usually involves repairing the Boot Manager files or correcting the boot order in BIOS/UEFI. You can resolve it with built-in Windows recovery tools; no third-party software is required.

What You’ll Need

A Windows 10 installation USB drive or recovery drive (created on another PC if needed)
Access to your PC’s BIOS/UEFI setup (usually by pressing Del, F2, F12, or Esc during startup)
A second working PC to create a bootable USB if you don’t already have one

Step-by-Step

Check for removable media. Remove any USB drives, SD cards, or discs from your PC. Restart it. If Windows starts, the issue was a boot order conflict. If not, continue.
Enter BIOS/UEFI. Restart your PC and press the key shown on screen (often Del, F2, F12, or Esc) to enter setup. Find the Boot tab or Boot Order menu.
Set the correct boot drive. Ensure your hard drive (or SSD) containing Windows is first in the boot order. If it’s already first, move it to the top anyway, save changes, and restart. If the error persists, proceed.
Boot from Windows 10 installation media. Insert your USB or recovery drive, restart, and boot from it (use the boot menu key, often F12 or F11, or change boot order in BIOS).
Open Command Prompt. When the Windows Setup screen appears, select your language and click Next. Then click Repair your computer in the bottom-left corner. Choose Troubleshoot > Advanced options > Command Prompt.
Run bootrec commands. In Command Prompt, type the following commands one at a time, pressing Enter after each:
bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd
If you see “Access is denied” after /fixboot, skip to step 8.
Rebuild the BCD manually (if needed). If /rebuildbcd finds no Windows installations or fails, type these commands:
bcdedit /export C:\BCD_Backup
ren C:\boot\bcd BCD.old
bootrec /rebuildbcd
When prompted, press Y to add the installation to the boot list.
Use the alternate fixboot method. If /fixboot gave “Access is denied,” type:
bootsect /nt60 SYS
or
bootsect /nt60 ALL
Then restart your PC.
Exit and restart. Type exit to close Command Prompt, then click Continue or restart your PC. Remove the installation media when prompted.

Common Mistakes

Running bootrec on the wrong drive. The commands operate on the system drive. If you have multiple drives, ensure the one with Windows is connected and set as primary.
Skipping the BIOS boot order check. Many cases are simply a USB stick left in the port. Always check this first.
Using a 32-bit recovery environment on a 64-bit system. Match the architecture of your Windows installation when creating recovery media.
Assuming data loss. These commands repair boot files; they do not delete personal files. Do not format any drive during this process.
Forgetting to remove the USB after repair. If the USB is still in the port, the PC may try to boot from it again and show the same error.

Tips

Back up your BCD before editing. The bcdedit /export command creates a backup that can restore the old configuration if something goes wrong.
Use the exact commands. Copy them carefully; a typo like /fixboot vs /fixboots will fail silently.
Disable Secure Boot temporarily. In BIOS/UEFI, disabling Secure Boot can sometimes resolve boot manager issues, especially after hardware changes. Re-enable it after the fix.
Check for disk errors. After booting to Windows, run chkdsk /f /r in an elevated Command Prompt to check the drive for bad sectors that may cause recurring boot problems.
Keep a recovery drive ready. Creating one now (Control Panel > Recovery > Create a recovery drive) saves you from needing another PC later.

Troubleshooting

If the error persists after following all steps, try these additional measures:

Check the drive connection. Power off your PC, open the case, and reseat the SATA or NVMe cable connecting your hard drive. A loose cable can cause intermittent boot failures.
Run Startup Repair. Boot from the installation media, choose Repair your computer > Troubleshoot > Advanced options > Startup Repair. Let it run; it may fix the boot files automatically.
Test your hard drive. Use the manufacturer’s diagnostic tool (downloadable from their website on another PC) to check for failing hardware. A dying drive can corrupt boot files repeatedly.
Check for BIOS/UEFI updates. An outdated firmware version can cause boot manager issues. Visit your motherboard manufacturer’s support page for the latest BIOS update instructions.
Try a different USB port. If booting from installation media fails, use a USB 2.0 port (often black) instead of USB 3.0 (blue), as some older systems have compatibility issues.
Reset BIOS to defaults. In BIOS/UEFI, look for “Load Optimized Defaults” or “Reset to Default.” Save and restart. This can resolve incorrect settings that block boot.

Frequently Asked Questions

Will this fix delete my files?
No. The bootrec and bcdedit commands only repair boot configuration files. Your documents, photos, and installed programs remain untouched.

Why did this error appear suddenly?
Common causes include a power outage during startup, a failed Windows update, improper shutdown, or a change in BIOS boot order (e.g., after adding a new drive).

Can I fix this without a Windows installation USB?
Yes, if you have a recovery drive. If not, you can create one on another PC using Microsoft’s Media Creation Tool. Without any media, you may need to borrow a friend’s PC to create one.

What if I have a dual-boot system with Linux?
The bootrec commands may remove the Linux entry from the boot menu. After repairing Windows, you may need to reinstall GRUB using a Linux live USB to restore dual-boot.

How long does the repair take?
The bootrec commands typically complete in under five minutes. Startup Repair can take 15-30 minutes. The entire process, including creating boot media, usually takes under an hour.

Is this error a sign my hard drive is failing?
Not necessarily. It’s often a software issue with the boot configuration. However, if the error returns frequently after repair, a failing drive or failing cable is a real possibility, so run a disk diagnostic.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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