Boot Configuration Data Editor Frequently Asked Questions

The Boot Configuration Data (BCD) store contains boot configuration parameters and controls how the operating system is started in Microsoft® Windows Vista® and Microsoft® Windows Server® 2008 operating systems. These parameters were previously in the Boot.ini file (in BIOS-based operating systems) or in the nonvolatile RAM (NVRAM) entries (in Extensible Firmware Interface–based operating systems). You can use the Bcdedit.exe command-line tool to affect the Windows® code which runs in the pre-operating system environment by adding, deleting, editing, and appending entries in the BCD store. Bcdedit.exe is located in the \Windows\System32 directory of the Windows Vista partition.

BCD was created to provide an improved mechanism for describing boot configuration data. With the development of new firmware models (for example, the Extensible Firmware Interface (EFI)), an extensible and interoperable interface was required to abstract the underlying firmware. This new design provides the foundation for a variety of new features in Windows Vista (for example, the Startup Repair tool and Multi-User Install shortcuts).

No. You need administrative credentials to modify BCD.

Depending on what you want to change, you can use the following tools to modify BCD:

All Windows entries are stored in the BCD store. On an EFI-based operating system, there is a single entry in the EFI firmware boot manager called “Windows Boot Manager”. This file is located in \EFI\Microsoft\Boot\Bootmgfw.efi. If you start Windows Boot Manager using the EFI boot manager, you should get a common look and feel on both your EFI-based and PC/AT-based operating systems. For example, the advanced boot options menu should work. The default timeout for the EFI boot manager is 2 seconds to make it easier to boot back and forth between Windows Server 2003 with Service Pack 1 and Windows Vista.

Yes. You can install Windows Vista on a different partition. It is best to install Windows Vista after you install the older operating systems. Older operating systems will continue to use Boot.ini for boot configuration.

No. You will need to alter your code so that it uses Boot.ini for the older operating systems, and so that it uses BCD on Windows Vista.

No. You need to modify BCD to alter the boot configuration for Windows Vista. You also need to modify Boot.ini (for BIOS-based operating systems) or NVRAM (for EFI-based operating systems) to alter boot configuration for the older operating systems.

No. The boot manager for Windows Vista runs first to determine which operating system to start. Therefore, if you want to boot to the older operating system, you must set the default order to the older operating system in the BCD store. For more information, see How to change the default operating system entry.

You can use Bcdedit.exe to modify the Windows code which runs in the pre- operating system environment by adding, deleting, editing, and appending entries in the BCD store. Bcdedit.exe is located in the \Windows\System32 directory of the Windows Vista partition.

Bcdedit.exe currently enables you to do the following:

•Create a BCD store for a later installation of Windows Server 2008.

•Add entries to a existing BCD store

•Modify existing entries in a BCD store.

•Delete entries from a BCD store.

•Export entries to a BCD store.

•Import entries from a BCD store.

•List currently active settings.

•Query entries of a particular type.

•Apply a global change (to all the entries).

•Change the default time-out value.

The boot environment has been split into two categories: Windows Boot Manager and various boot applications that run in the boot environment. Windows Boot Manager is basically a mini-operating system that controls your boot experience and enables you to choose which boot application to run. There are various boot applications (for example, Windows Boot Loader) and each one does something different. For example, a Windows Boot Loader application loads Windows.

When you specify /enum, you will get the following:

Yes. For detailed command and option information at the command prompt, type bcdedit.exe /? and bcdedit.exe /? Command. For example, type bcdedit.exe /? CREATESTORE.

At the command prompt type:

bcdedit /dbgsettings DebugType [debugport Port] [baudrate Baud]

[channel Channel] [targetname TargetName]

The following command sets the global debugger settings to serial debugging

over com1 at 115,200 baud:

bcdedit /dbgsettings serial debugport 1 baudrate 115200

The following command sets the global debugger settings to 1394 debugging

using channel 23:

bcdedit /dbgsettings 1394 CHANNEL 32

The following command sets the global debugger settings to USB debugging

using target name "debugging":

bcdedit /dbgsettings USB targetname debugging

At the command prompt, type:

bcdedit /enum Type /v

For example, the following command lists all entries:

bcdedit /enum all /v

At the command prompt, type:

bcdedit /default ID

The following command sets the specified entry as the default boot manager

entry:

bcdedit /default {cbd971bf-b7b8-4885-951a-fa03044f5d71}

The following command sets the legacy Windows loader (Ntldr) as the default

entry: {466f5a88-0af2-4f76-9038-095b170dc21c} is the predefined GUID for Ntldr.

bcdedit /default {466f5a88-0af2-4f76-9038-095b170dc21c}

At the command prompt, type:

bcdedit /bootsequence {ID} {ID} {ID} …

The following command sets the specified operating system as the default for the next restart. After that restart, it will be reset to DISPLAYORDER.

bcdedit /bootsequence {cbd971bf-b7b8-4885-951a-fa03044f5d71}

The following command sets two operating system entries and the

legacy Windows loader (Ntldr) in the boot manager one-time boot sequence:

bcdedit /bootsequnce {802d5e32-0784-11da-bd33-000476eba25f}

{cbd971bf-b7b8-4885-951a-fa03044f5d71} {legacy}

To change the length of time the computer waits until the default operating system is selected, type the following:

bcdedit /timeout TimeOut

For example, the following command sets the boot manager TimeOut to 15 seconds:

bcdedit /timeout 15

At the command prompt, type:

Bcdedit.exe /display {ID} {ID1} {ID2} …

or

Bcdedit.exe /displayorder {ID} [/addlast|/addfirst|/remove]

The following command sets three operating system entries in the boot manager display order:

Bcdedit.exe /displayorder {c84b751a-ff09-11d9-9e6e-0030482375e6} {c74b751a-ff09-11d9-9e6e-0030482375e4} {c34b751a-ff09-11d9-9e6e-0030482375e7}

The following command sets two operating system entries and the legacy Windows loader in the boot manager display order:

bcdedit /displayorder {802d5e32-0784-11da-bd33-000476eba25f}

{cbd971bf-b7b8-4885-951a-fa03044f5d71} {legacy}

The following command adds the entry represented by the GUID to end of the boot menu display order.

bcdedit.exe /displayorder {c84b751a-ff09-11d9-9e6e-0030482375e6}-addlast

At the command prompt, type:

bcdedit /delete ID [/f]

For example, the following command deletes the entry with id {802d5e32-0784-11da-bd33-000476eba25f}.

bcdedit /delete {802d5e32-0784-11da-bd33-000476eba25f}

At the command prompt, type:

bcdedit /debug [{ID}] {on|off}

For example, the following command enables boot debugging for the specified operating system boot entry:

bcdedit /debug {cbd971bf-b7b8-4885-951a-fa03044f5d71} on

At the command prompt, type:

bcdedit /set {ID} pae [Default|ForceEnable|ForceDisable]

For example:

bcdedit /set {802d5e32-0784-11da-bd33-000476eba25f} pae forceenable

At the command prompt, type the following. Removememory removes memory from the total available memory that the operating system can use.

bcdedit /set {GUID} removememory bytes

This example removes 256 MB of memory from the total available:

bcdedit /set {802d5e32-0784-11da-bd33-000476eba25f } removememory 256

At the command prompt, type the following. Truncatememory disregards all memory at or above the specified physical address.

bcdedit /set {ID} truncatememory bytes

This example sets the truncate memory to 1024 MB:

bcdedit /set {802d5e32-0784-11da-bd33-000476eba25f} truncatememory 1073741824

At the command prompt, type:

bcdedit /set {ID} kernel "Path"

For example:

bcdedit /set {802d5e32-0784-11da-bd33-000476eba25f} kernel "mykrnl.dll"

To create a new Windows Vista operating system entry, use the following procedure:

The /enum command lists entries in the BCD store. To list entries, type:

bcdedit /enum [Type]

The following command lists all operating system loader boot entries:

bcdedit /enum osloader

The following command lists all boot manager entries:

bcdedit /enum bootmgr

To install an older Windows operating system on a computer running Windows Vista, use the following procedure.

To create an entry to boot a Windows Imaging Format (WIM) image, you will need to create an OSloader type entry with RAMDISK options pointing to the boot partition. To do this, use the following procedure. In this procedure, the arcpath multi(0)disk(0)rdisk(0)partition(1) refers to the C: drive on the computer, and Boot.wim is a regular Boot.wim with Winload.exe in the System32 folder inside the WIM image.

To override the global entry for a specific debugger setting, type one of the following.

The following command sets the debugger setting for c74b751a-ff09-11d9-9e6e-0030482375e4 to serial debugging over com1 at 115,200 baud:

Bcdedit /set {c74b751a-ff09-11d9-9e6e-0030482375e4} debugtype:serial

Bcdedit /set {c74b751a-ff09-11d9-9e6e-0030482375e4} baudrate:115200

Bcdedit /set {c74b751a-ff09-11d9-9e6e-0030482375e4} debugport:1