What Is the Windows Boot Manager (BOOTMGR)?

Definition of Windows Boot Manager (BOOTMGR)

Windows Boot Manager (BOOTMGR) is a small piece of software, called a boot manager, that's loaded from the volume boot code, which is part of the volume boot record.

BOOTMGR helps your Windows 10, Windows 8, Windows 7, or Windows Vista operating system start.

BOOTMGR eventually executes winload.exe, the system loader used to continue the Windows boot process.

Instructions in this article apply to Windows 10, Windows 8, Windows 7, and Windows Vista.

Where Is Windows Boot Manager (BOOTMGR) Located?

Configuration data required for BOOTMGR can be found in the Boot Configuration Data (BCD) store, a registry-like database that replaced the boot.ini file used in older versions of Windows like Windows XP.

The BOOTMGR file itself is both read-only and hidden. It is located in the root directory of the partition marked as Active in Disk Management. On most Windows computers, this partition is labeled as System Reserved and doesn't have a drive letter.

If you don't have a System Reserved partition, BOOTMGR is probably located on your primary drive, which is usually C:.

Can You Disable Windows Boot Manager?

Why might you want to disable or turn off the Windows Boot Manager? Simply put, it can unnecessarily slow down the boot process as it waits to ask you which operating system to boot. If you don't need to choose which operating system to boot to, maybe because you always like to start the same one, then you can avoid it by pre-selecting the one you always want to start.

However, you can't actually remove the Windows Boot Manager. What you can do is reduce the time that it waits on the screen for you to answer which operating system you want to start. You can do this by pre-choosing the operating system and then lowering the timeout time, basically skipping the Windows Boot Manager altogether.

This is accomplished through the System Configuration (msconfig.exe) tool. Here's how to do this:

Be careful when using the System Configuration tool — you might make unnecessary changes that can just cause more confusion in the future.

  1. Open Administrative Tools, which is accessible through the System and Security link in Control Panel.

    Administrative Tools in Windows 10 System and Security app

    If you don't see the System and Security link on the first page of Control Panel, select Administrative Tools instead.

  2. Open System Configuration.

    System Configuration icon in Administrative Tools in Windows 10

    Another option for opening System Configuration is to use its command line command. Open the Run dialog box (WIN+R) or Command Prompt and then enter the msconfig.exe command.

  3. Select the Boot tab on the System Configuration window that opens.

    Boot tab in System Configuration app in Windows 10
  4. Choose the operating system you want to always boot to.

    Remember that you can always change this again later if you decide to boot to a different one.

  5. Adjust the Timeout time to the lowest possible time, in seconds, which is probably 3.

    Timeout set to 3 seconds in System Configuration's Boot tab
  6. Choose OK or Apply to save the changes.

    System Configuration screen might pop up after saving these changes, to inform you that you might need to restart your computer. It's safe to choose Exit without restart — you'll see the effect of making this change the next time you restart.

  7. Boot manager should now be disabled.

Additional Information on BOOTMGR

A common startup error in Windows is the BOOTMGR Is Missing error.

BOOTMGR, together with winload.exe, replaces the functions performed by NTLDR in older versions of Windows, like Windows XP. Also new is the Windows resume loader, winresume.exe.

When at least one Windows operating system is installed and selected in a multi-boot scenario, the Windows Boot Manager is loaded and reads and applies the specific parameters that apply to the operating system installed to that particular partition.

If the Legacy option is chosen, the Windows Boot Manager starts NTLDR and continues through the process like it would when booting any version of Windows that uses NTLDR, like Windows XP. If there's more than one installation of Windows that's pre-Vista, another boot menu is given (one that's generated from the contents of the boot.ini file) so that you can select one of those operating systems.

The Boot Configuration Data store is more secure than the boot options found in previous versions of Windows because it lets users in the Administrators group lock down the BCD store and give out certain rights to other users to determine which ones can manage boot options.

As long as you're in the Administrators group, you can edit the boot options in Windows Vista and newer versions of Windows using the BCDEdit.exe tool included in those versions of Windows. If you're using an older version of Windows, the Bootcfg and NvrBoot tools are used instead.