Part 4. BCD (Boot Configuration Data) and BCDEdit : 1. What is BCD (Boot Configuration Data)? From Windows Vista, a new firmware-independent boot configuration and storage system called Boot Configuration Data (BCD) is introduced. BCD provides a common, firmware-independent boot option interface and it is more secure than previous boot option storage configurations. On Windows Vista and later versions of Windows, boot options are stored in the Boot Configuration Data (BCD) store on BIOS-based and EFI-based computers. For BIOS-based systems, boot configuration data was contained in a text file named Boot.ini; For Extensible Firmware Interface (EFI)–based systems, boot configuration data was contained in nonvolatile RAM (NVRAM). You can manage BCD remotely and manage BCD when the system boots from media other than the media on which the BCD store resides. This feature is extremely important for debugging and troubleshooting, especially when a BCD store must be restored while running Startup Repair from a CD, from USB-based storage media, or even remotely. 2. What is BCDEdit? BCDEdit is a command-line tool that can be used to add, delete, edit, and modify data in a BCD store. Bcdedit.exe is located in the \Windows\System32 directory of the Windows system partition. Here is the list of its common usage: Usage Command Description Operating on a store /createstore Creates a new empty BCD store. /export Exports the contents of the system BCD store to a specified file. /import Restores the state of the system BCD store from a specified file. Operating on boot entries in a store /copy Makes copies of boot entries. /create Creates new boot entries. /delete Deletes boot entries. Operating on elements /deletevalue Deletes elements from a boot entry. /set Creates or modifies a boot entry’s elements. Commands that control output /enum Lists the boot entries in a store. Commands that control Boot Manager /bootsequence Specifies a one-time boot sequence. /default Specifies the default boot entry. /displayorder Specifies the order in which Boot Manager displays its menu. /timeout Specifies the Boot Manager Timeout value. /toolsdisplayorder Specifies the order in which Boot Manager displays the tools menu. Commands that control Emergency Management Services /bootems Enables or disables Emergency Management Services (EMS) for a specified boot application. /ems Enables or disables EMS for an operating system boot entry. /emssettings Specifies global EMS parameters. Commands that control debugging /bootdebug Enables or disables boot debugging for a boot application. /dbgsettings Specifies global debugger parameters. /debug Enables or disables kernel debugging for an operating system boot entry. Commands that modify other commands /store Specifies the BCD store upon which a command acts. /v Displays boot entry identifiers in full, rather than using well-known identifiers. 3. How to backup and restore BCD? To backup BCD, you can just export it to a location with the following command: bcdedit /export C:\BCD_Backup You can restore the BCD with the backup file by using the following command: bcdedit /import C:\BCD_Backup

4. How to create a Boot Entry for Windows XP? To do this, please start an elevated command prompt and run the following commands one by one: I. bcdedit /create {ntldr} /d “Windows XP Professional” II. bcdedit /displayorder {ntldr} /addlast III. bcdedit /set {ntldr} /device partition=c: IV. bcdedit /set {ntldr} path \ntldr 5. What is Bootrec.exe? Bcdedit.exe is a command line tool which can be used to repair the MBR, Boot Sector and BCD store. It has the following commands: /FIXMBR: Writes a master boot record to the system partition Bootrec.exe /FIXMBR /FIXBOOT: Writes a new boot sector onto the system partition Bootrec.exe /FIXBOOT /SCANOS: Scans all disks for Windows installation and displays entries currently not in the BCD store Bootrec.exe /SCANOS /REBUILDBCD: Scans all disks for Windows installations and allows users to choose which entries to add to the BCD store. Bootrec.exe /REBUILDBCD Generally, boot issues can be resolved by Startup Repair in WinRE; however, if Startup Repair doesn’t work, the bootrec.exe tool may be useful. 6. How to repair the BCD store? There are three methods which can help on this: I. Boot the system to WinRE and use “Startup Repair”. II. Use Bootrec.exe in WinRE to repair the BCD: To recover from a damaged BCD store or missing boot entry with Bootrec.exe, you can use the following Bootrec command: bootrec /rebuildbcd III. Use BCDEdit to create it manually in WinRE. Boot to WinRE and run the following commands one by one in the command prompt: bcdedit /create /d “Windows 7” /application osloader bcdedit /enum bcdedit /displayorder {<GUID>} /addlast bcdedit /set {<GUID>} device partition=C: bcdedit /set {<GUID>} path \Windows\system32\winload.exe bcdedit /set {<GUID>} systemroot \Windows bcdedit /set {<GUID>} osdevice partition=c: