How to Fix “BOOTMGR Is Missing” Error in Windows 11

If your Windows computer fails to start with the error message “BOOTMGR is missing. Press Ctrl+Alt+Del to restart,” it means Windows cannot locate or load the files required to start the operating system. BOOTMGR, short for Windows Boot Manager, is a critical boot utility responsible for loading Windows during startup. When you turn on your PC, BOOTMGR locates the Windows Boot Configuration Data (BCD), loads the necessary boot files, and hands control over to the operating system. If for some reason it cannot find or read these essential files, Windows stops the boot process and displays the “BOOTMGR is missing” error instead.

This problem usually occurs because of an incorrect boot order in the BIOS/UEFI, corrupted boot files, a damaged Boot Configuration Data (BCD) store, bad sectors on the hard drive or SSD, missing system partitions after cloning a drive, or loose hardware connections.

However, in most cases, you don’t need to reinstall Windows. The error can often be fixed using Windows Recovery tools or a few troubleshooting steps. In this guide, we’ll explain what causes the BOOTMGR is missing error and walk you through the most effective solutions to get your Windows 11 PC booting normally again.

Why Does the “BOOTMGR Is Missing” Error Occur?

The “BOOTMGR is missing” error can appear for several reasons, but they all have one thing in common your computer cannot access the files required to start Windows. Some causes are simple and can be fixed in a few minutes, while others may indicate corruption or hardware problems.

Here are the most common reasons:

• Incorrect boot order: Your PC may be trying to boot from a USB drive, external hard drive, or another device instead of the drive containing Windows.
• Corrupted boot files: Essential startup files may become damaged after a failed Windows update, unexpected shutdown, or malware infection.
• Damaged Boot Configuration Data (BCD): The BCD stores information that tells Windows where the operating system is located. If it becomes corrupted, Windows cannot start.
• Hard drive or SSD problems: Bad sectors or a failing storage drive can prevent BOOTMGR from being read.
• Loose or faulty hardware connections: A disconnected SATA cable or improperly installed SSD/HDD can stop the system from detecting the Windows drive.
• Drive cloning or partition changes: Cloning Windows to a new SSD, deleting partitions, or changing partition settings can accidentally remove or corrupt the boot files.

Now let’s start with the simplest solutions before moving on to more advanced repair methods.

Before You Begin: Try These Quick Checks

Before attempting advanced troubleshooting, try these simple checks. In many cases, the “BOOTMGR is missing” error is caused by an incorrect boot device or a temporary startup issue that can be resolved in just a few minutes.

1. Remove External Storage Devices

Disconnect any USB flash drives, external hard drives, memory cards, or DVDs connected to your computer. If your PC is trying to boot from one of these devices instead of the Windows drive, it may display the BOOTMGR is missing error.

After removing the devices, restart your computer and check whether Windows starts normally.

2. Restart Your Computer

Sometimes the error is caused by a temporary glitch during startup. Press Ctrl + Alt + Del or use the power button to restart your PC and see if the problem resolves itself.

3. Check Whether Your Drive Is Detected

If you recently installed a new SSD or HDD, entered the BIOS/UEFI settings, or changed hardware, verify that your Windows drive is still detected by the system. If the drive isn’t listed, the problem may be related to the storage device or its connection rather than Windows itself.

If these quick checks don’t resolve the issue, continue with the solutions below, starting with the most common and easiest fixes.

Fix 1: Check the Boot Order in BIOS/UEFI

If your computer tries to boot from the wrong device, such as a USB flash drive, an external hard drive, or an empty storage drive, it won’t be able to find BOOTMGR and may display the “BOOTMGR is missing” error. Checking your Windows drive as the first boot device often resolves the problem.

Step 1: Enter the BIOS/UEFI Settings

1. Turn off your computer completely.
2. Turn it back on and immediately press the key used to open the BIOS/UEFI settings. Depending on your PC manufacturer, this is usually one of the following keys:
   • Delete (Del)
   • F2
   • F10
   • F12
   • Esc

Tip: If you’re unsure which key to press, watch the first startup screen or check your computer or motherboard manufacturer’s documentation.

Step 2: Open the Boot Menu

Once you’re in the BIOS/UEFI setup, look for a tab named Boot, Boot Options, or Boot Priority. The exact name and layout vary depending on your motherboard or laptop manufacturer.

Step 3: Set the Windows Drive as the First Boot Device

Locate the drive that contains your Windows installation and move it to the top of the boot priority list. If you recently installed a new SSD or HDD, make sure the correct drive is selected.

Step 4: Save the Changes and Restart

Save your changes (usually by pressing F10) and exit the BIOS/UEFI. Your computer will restart automatically.

If the incorrect boot order was causing the problem, Windows should now load normally. If you still see the “BOOTMGR is missing” message, continue to the next solution.

Fix 2: Run Startup Repair

If the boot order is correct but Windows still won’t start, the next step is to run Startup Repair. This built-in Windows Recovery tool scans your computer for problems that prevent Windows from booting and automatically repairs common startup issues, including missing or corrupted boot files.

How to Access Startup Repair

If your PC cannot boot into Windows, you’ll need to enter the Windows Recovery Environment (WinRE).

Option 1: Use a Windows Installation USB (Recommended)

1. Connect your Windows 11 or Windows 10 installation USB.
2. Boot your computer from the USB drive.
3. On the Windows Setup screen, select your language and keyboard layout, then click Next.
4. Instead of selecting Install now, click Repair your computer in the lower-left corner.
5. Go to Troubleshoot → Advanced options → Startup Repair.

Option 2: Use Automatic Repair

If Windows fails to start several times in a row, it may automatically load the Windows Recovery Environment. From there, navigate to:

Troubleshoot → Advanced options → Startup Repair

Wait for the Repair to Complete

Startup Repair will scan your system for boot-related problems and attempt to fix them automatically. Depending on your computer and the issue, this process may take several minutes.

When the repair finishes, restart your computer and check whether Windows starts normally.

Note: Startup Repair doesn’t always resolve the “BOOTMGR is missing” error, especially if the Boot Configuration Data (BCD) is severely corrupted. If the problem persists, continue with the next method to manually rebuild the Windows boot files.

Fix 3: Rebuild the Boot Configuration Data (BCD)

If Startup Repair couldn’t fix the problem, the Boot Configuration Data (BCD) may be damaged or missing. The BCD is a database that stores information about your Windows installation and tells Boot Manager where to find the operating system during startup. Rebuilding it can often resolve the “BOOTMGR is missing” error.

Step 1: Open Command Prompt

1. Boot your computer using a Windows installation USB or enter the Windows Recovery Environment (WinRE).
2. Select Repair your computer.
3. Go to Troubleshoot → Advanced options → Command Prompt.

Step 2: Run the Boot Repair Commands

Type the following commands one at a time, pressing Enter after each command:

bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd

Here’s what each command does:

• bootrec /fixmbr – Writes a new Master Boot Record (MBR) without affecting your personal files or partitions.
• bootrec /fixboot – Writes a new boot sector to the system partition. This can repair boot sector corruption.
• bootrec /scanos – Scans all drives for Windows installations that aren’t currently listed in the BCD store.
• bootrec /rebuildbcd – Recreates the Boot Configuration Data store and adds detected Windows installations back to the boot menu.

If you’re prompted to add a Windows installation to the boot list, type Y and press Enter.

Step 3: Restart Your Computer

After all commands complete successfully, close the Command Prompt and restart your PC.

If Windows starts normally, the damaged boot configuration was the cause of the problem. If you still receive the “BOOTMGR is missing” error or one of the commands returns an error such as “Access is denied”continue to the next solution.

Fix 4: Check the Drive for File System Errors

If the boot files are intact but Windows still can’t read them, your hard drive or SSD may have file system errors or bad sectors. Running the Check Disk (CHKDSK) utility scans the drive for errors, repairs logical file system problems, and attempts to recover readable information from damaged sectors.

Note: This process may take anywhere from a few minutes to several hours, depending on your drive size and the number of errors found.

Step 1: Open Command Prompt

1. Boot your PC using a Windows installation USB or enter the Windows Recovery Environment (WinRE).
2. Select Repair your computer.
3. Go to Troubleshoot → Advanced options → Command Prompt.

Step 2: Run CHKDSK

If Windows is installed on the C: drive, type the following command and press Enter:

chkdsk C: /f /r

If Windows is installed on another drive letter in the recovery environment, replace C: with the correct drive letter.

What the command does:

• /f – Fixes file system errors found on the drive.
• /r – Locates bad sectors, attempts to recover readable data, and marks damaged sectors so they won’t be used again.

Step 3: Restart Your Computer

After the scan finishes, close Command Prompt and restart your PC.

If CHKDSK repairs errors successfully, Windows may boot normally. However, if the scan reports numerous bad sectors or repeatedly finds new disk errors, your storage drive could be failing. In that case, back up your data as soon as possible after regaining access to Windows and consider replacing the drive.

Fix 5: Repair Corrupted Windows System Files

Corrupted or missing Windows system files can sometimes prevent the operating system from starting correctly. Running the System File Checker (SFC) scans protected Windows files and automatically replaces corrupted versions with healthy copies from the Windows component store.

Because your PC can’t boot into Windows, you’ll need to run SFC from the Windows Recovery Environment (WinRE).

Step 1: Open Command Prompt

1. Boot your computer using a Windows installation USB or enter the Windows Recovery Environment (WinRE).
2. Select Repair your computer.
3. Go to Troubleshoot → Advanced options → Command Prompt.

Step 2: Identify the Windows Drive Letter

In WinRE, Windows may not be assigned the C: drive letter. To find the correct drive, type:

diskpart
list volume
exit

Look for the volume containing your Windows installation and note its drive letter.

Step 3: Run the Offline SFC Scan

Replace C: with your Windows drive letter if it’s different, then run:

sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows

The scan may take several minutes to complete. If corrupted system files are found, SFC will attempt to repair them automatically.

Step 4: Restart Your Computer

Once the scan finishes, close Command Prompt and restart your PC.

If Windows still fails to boot with the “BOOTMGR is missing” error, continue to the next solution to repair the boot partition itself.

Fix 6: Mark the System Partition as Active (MBR Systems Only)

On computers that use the Legacy BIOS boot mode and an MBR-partitioned disk, the system partition must be marked as Active. This tells the BIOS which partition contains the Windows boot files. If the wrong partition is marked active or none is active your PC may display the “BOOTMGR is missing” error during startup.

Important: This solution only applies to MBR disks using Legacy BIOS. If your computer uses UEFI with a GPT disk (the default on most Windows 11 PCs), skip this method and continue to the next fix.

Step 1: Open Command Prompt

1. Boot your PC using a Windows installation USB or enter the Windows Recovery Environment (WinRE).
2. Select Repair your computer.
3. Go to Troubleshoot → Advanced options → Command Prompt.

Step 2: Launch DiskPart

Type the following command and press Enter:

diskpart

Step 3: Select the Windows Disk

Display all available disks:

list disk

Select the disk containing Windows (replace 0 with the correct disk number if necessary):

select disk 0

Step 4: Select the System Partition

Display the partitions on the selected disk:

list partition

Select the System Reserved partition (typically around 100–500 MB) or the partition containing the boot files:

select partition 1

Step 5: Mark the Partition as Active

Run the following command:

active

If the command completes successfully, DiskPart will display a confirmation message.

Finally, type:

exit

Restart your computer and check whether Windows starts normally.

Note: If you’re unsure whether your PC uses MBR or GPT, don’t guess. Using the active command on the wrong partition can create additional boot problems. If your computer uses UEFI/GPT, continue with the next solution instead.

Fix 7: Reset or Reinstall Windows (Last Resort)

If you’ve tried all the previous solutions and your PC still displays the “BOOTMGR is missing” error, the Windows installation or boot partition may be too severely damaged to repair. In this situation, resetting or reinstalling Windows is often the most effective way to restore your computer to a working state.

Important: If you have important files on your computer, try to back them up before resetting or reinstalling Windows. You can use another computer, connect the drive externally, or access your files through Windows Recovery or a Linux live USB if necessary.

Option 1: Reset This PC

If you can access the Windows Recovery Environment (WinRE), you can reset Windows without using installation media.

1. Boot into Windows Recovery Environment (WinRE).
2. Select Troubleshoot.
3. Click Reset this PC.
4. Choose one of the following options:
   • Keep my files – Reinstalls Windows while keeping your personal files. Installed apps and settings will be removed.
   • Remove everything – Erases all files, apps, and settings before reinstalling Windows.

Follow the on-screen instructions to complete the reset.

Option 2: Perform a Clean Installation

If the reset process isn’t available or doesn’t resolve the issue, create a Windows installation USB drive on another computer and perform a clean installation.

A clean installation completely removes the existing Windows installation and installs a fresh copy of Windows. While this method resolves most software-related boot problems, it also deletes installed applications and, unless you back them up first, your personal files.

What If the Error Still Appears?

If the “BOOTMGR is missing” error continues even after reinstalling Windows, the problem is likely hardware-related. Possible causes include:

• A failing hard drive or SSD
• A faulty SATA or power cable
• An incorrectly configured BIOS/UEFI
• A defective motherboard or storage controller

In these cases, inspect the hardware connections, test the storage drive using the manufacturer’s diagnostic tools, or replace the failing component if necessary.

How to Prevent the “BOOTMGR Is Missing” Error

While the “BOOTMGR is missing” error can usually be repaired, taking a few preventive measures can significantly reduce the chances of encountering it again.

Keep Windows Updated

Install Windows updates regularly to ensure your system has the latest bug fixes, security patches, and boot-related improvements. Avoid turning off your computer while updates are being installed, as interrupting the process can corrupt important system files.

Shut Down Your PC Properly

Always shut down Windows using the Start menu instead of forcing the computer to power off. Unexpected shutdowns caused by power outages or holding the power button can damage boot files and the Boot Configuration Data (BCD).

Check Your Hard Drive or SSD Regularly

Storage devices can develop file system errors or bad sectors over time. Running tools like CHKDSK and monitoring your drive’s health can help detect problems before they lead to boot failures.

Disconnect Unnecessary Boot Devices

Before restarting your computer, remove USB flash drives, external hard drives, DVDs, and memory cards that aren’t needed. This prevents your PC from accidentally trying to boot from the wrong device.

Back Up Important Data

No troubleshooting method is guaranteed to work in every situation. Regularly backing up your important files ensures you can recover your data even if Windows fails to start or you need to reinstall the operating system.

Create a Windows Recovery Drive

Creating a Windows Recovery USB in advance gives you quick access to Startup Repair, Command Prompt, and other recovery tools if your computer ever experiences startup problems again.

Frequently Asked Questions (FAQs)