Windows Boot Manager#winload.exe

On system with BIOS firmware, the BIOS invokes MBR boot code from a hard disk drive at startup. The MBR boot code and the VBR boot code are OS-specific. In Microsoft Windows, the MBR boot code tries to find an active partition (the MBR is only 512 bytes), then executes the VBR boot code of an active partition. The VBR boot code tries to find and execute the bootmgr file from an active partition.{{Cite web |title=Boot Sequence of Windows Multi-Boot – Multibooters.com |url=http://www.multibooters.com/guides/boot-sequence-of-mixed-windows-multiboot.html |archive-url=https://web.archive.org/web/20240227204046/http://www.multibooters.com/guides/boot-sequence-of-mixed-windows-multiboot.html |archive-date=2024-02-27 |url-status=dead |access-date=2020-11-19 |website=www.multibooters.com}}

On systems with UEFI firmware, UEFI invokes bootmgfw.efi from an EFI system partition at startup, starting the Windows Boot Manager.

Once launched the Windows Boot Manager reads the Boot Configuration Data to determine what operating systems are present and if it should present the user with a menu allowing them to select which operating system to boot. Before Windows Vista, this data was contained in {{mono|boot.ini}}.

These menu entries can include:

• Options to boot Windows Vista and later by invoking winload.exe.
• Options to resume Windows Vista and later from hibernation by invoking winresume.exe.
• Options to boot a prior version of the Windows NT family by invoking its NTLDR.
• Options to load and to execute a volume boot record.

{{further|Booting process of Windows NT}}

The operating system is loaded by individual boot loaders for each install of Windows, called the Windows Boot Loader.

The Windows Boot Manager invokes winload.exe—the operating system boot loader—to load the operating system kernel executive (ntoskrnl.exe) and core device drivers. In that respect, winload.exe is functionally equivalent to the operating system loader function of NTLDR in prior versions of Windows NT. In UEFI systems, the file is called winload.efi and the file is always located at \windows\system32 or \windows\system32\boot.

If the computer has recently hibernated, then bootmgr will instead invoke winresume.exe. In UEFI systems, the file is called winresume.efi and is always located at \windows\system32 or \windows\system32\boot.{{cite web |last1=Hudek |first1=Ted |last2=Marshall |first2=Don |last3=Graf |first3=Eliot |date=23 April 2019 |title=Overview of Boot Options in Windows |url=https://docs.microsoft.com/en-us/windows-hardware/drivers/devtest/boot-options-in-windows |url-status=live |archive-url=https://web.archive.org/web/20200421135336/https://docs.microsoft.com/en-us/windows-hardware/drivers/devtest/boot-options-in-windows |archive-date=21 April 2020 |access-date=21 April 2020 |website=Microsoft Docs Hardware Dev Center |publisher=Microsoft |language=EN |ref=11}}

Boot Configuration Data (BCD) is a firmware-independent database for boot-time configuration data.{{Cite web |last=Marshall |first=Don |title=Overview of Boot Options in Windows – Windows drivers |url=https://learn.microsoft.com/en-us/windows-hardware/drivers/devtest/boot-options-in-windows |access-date=2023-03-20 |website=learn.microsoft.com |language=en-us}} It is used by Microsoft's Windows Boot Manager and replaces the boot.ini that was used by NTLDR.

Boot Configuration Data is stored in a data file that has the same format as Windows Registry hives and is eventually mounted at registry key {{mono|HKEY_LOCAL_MACHINE\BCD00000}}{{cite news |last=Russinovich |first=Mark |author-link=Mark Russinovich |date=8 November 2011 |title=Fixing Disk Signature Collisions |work=Mark's Blog |publisher=Microsoft Corporation |agency=Microsoft TechNet |url=https://docs.microsoft.com/en-us/archive/blogs/markrussinovich/fixing-disk-signature-collisions |access-date=5 February 2021}} (with restricted permissions{{cite web |title=Why can't I edit the system BCD store via regedit? |url=http://superuser.com/questions/654971/why-cant-i-edit-the-system-bcd-store-via-regedit}}). For UEFI boot, the file is located at /EFI/Microsoft/Boot/BCD on the EFI System Partition. For traditional BIOS boot, the file is at /boot/BCD on the active partition.{{cite web |author=Microsoft |title=Knowledge Base Article ID: 2004518 |url=https://support.microsoft.com/en-us/kb/2004518 |archive-url=https://web.archive.org/web/20100116044204/http://support.microsoft.com/kb/2004518 |archive-date=16 January 2010}}

{{Infobox software

| name = bcdedit

| screenshot =

| logo =

| screenshot size =

| caption =

| developer = Microsoft

| released =

| latest release version =

| latest release date =

| operating system = Microsoft Windows

| genre = Command

| license = Proprietary commercial software

| website = {{URL|https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/bcdedit}}

}}

Boot Configuration Data may be altered using a command-line tool (bcdedit.exe), using the Registry Editor (regedit.exe), using Windows Management Instrumentation, or with third-party tools such as EasyBCD, BOOTICE,{{cite web | url = http://bbs.ipauly.com/viewforum.php?f=2 | title = BOOTICE board index | author = Pauly | access-date = 2013-12-27 | archive-date = 2013-12-28 | archive-url = https://web.archive.org/web/20131228000320/http://bbs.ipauly.com/viewforum.php?f=2 | url-status = dead }} or Visual BCD Editor.{{cite web | url = http://www.boyans.net | title = Visual BCD Editor | author = Bo Yans }}

Boot Configuration Data allows for third-party integration, so anyone can implement tools like diagnostics or recovery options

• Booting process of Windows NT
• Windows Vista I/O technologies

{{Refbegin}}

• {{cite web |author-last=de Boyne Pollard |author-first=Jonathan |title=The Windows NT 6 boot process |url=https://jdebp.eu/FGA/windows-nt-6-boot-process.html |work=Frequently Given Answers}}

{{Refend}}

{{Windows Components}}

{{Firmware and booting}}

Category:Boot loaders

Category:Windows NT architecture

Category:Windows Vista