Windows 7 / Getting Started

Boot Configuration Data

The BCD registry file replaces the Boot.ini files used in Windows XP and earlier versions of Windows to track operating system locations, and it allows for a variety of new Windows Vista and Windows 7 features, including the Startup Repair tool and the Multi-User Install shortcuts. The BCD is stored in a data file that uses the same format as the registry and is located on either the Extensible Firmware Interface (EFI) system partition (for computers that support EFI) or on the system volume. On BIOS-based operating systems, the BCD registry file is located at \Boot\Bcd on the active partition. On EFI-based operating systems, the BCD registry file is located in the \EFI\Microsoft\Boot\ folder on the EFI system partition.

The BCD registry file can contain the following types of information:

  • Entries that describe Windows Boot Manager (\Bootmgr) settings
  • Entries to start the Windows Boot Loader (\Windows\System32\WinLoad.exe), which can then load Windows Vista
  • Entries to start Windows Resume Application (\Windows\System32\WinResume.exe), which can then restore Windows Vista from hibernation
  • Entries to start Windows Memory Diagnostic (\Boot\MemTest.exe)
  • Entries to start Ntldr to load previous versions of Windows
  • Entries to load and execute a Volume Boot Record, which typically starts a non-Microsoft boot loader

Additionally, you can add more entries to load custom applications, such as recovery tools.

You can modify the BCD registry file in several different ways:

  • Startup And Recovery With the Startup And Recovery dialog box (available on the Advanced tab of the System Properties dialog box), you can select the default operating system to start if you have multiple operating systems installed on your computer. You can also change the time-out value. This dialog box has changed very little when compared to Windows XP; however, it now changes the BCD registry file instead of the Boot.ini file.
  • System Configuration utility (Msconfig.exe) Msconfig.exe is a troubleshooting tool that you can use to configure startup options. The Boot tab in Windows 7 provides similar functionality to the Boot.ini tab in Windows XP, such as starting in safe mode, enabling a boot log, or disabling the graphical user interface (GUI).
  • BCD Windows Management Instrumentation provider The BCD Windows Management Instrumentation (WMI) provider is a management interface that you can use to script utilities that modify BCD. This is the only programmatic interface available for BCD; you should always use this interface rather than attempting to access the BCD registry file directly. For more information, see "BCD WMI Provider Classes" at
  • BCDEdit.exe BCDEdit.exe is a command-line utility that replaces Bootcfg.exe in Windows XP. BCDEdit can be run from within Windows 7 at an administrative command prompt, from within Windows RE or even from within earlier versions of Windows (if the BCDEdit.exe file is available). BCDEdit provides more configuration options than the Startup And Recovery dialog box.
  • Non-Microsoft tools Third-party software vendors have released tools to simplify editing the BCD registry file, including:
    • BootPRO, available at
    • EasyBCD, available at

You cannot use Bootcfg.exe to modify BCD. However, Bootcfg.exe will remain in the operating system to support configuring older operating systems that might be installed on the same computer.

For EFI computers, BCDEdit also replaces NvrBoot. In previous versions of Windows, you could use NvrBoot to edit the EFI boot manager menu items.

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In this tutorial:

  1. Configuring Startup and Troubleshooting Startup Issues
  2. What is New with Windows Startup
  3. Boot Configuration Data
  4. BCD Stores
  5. System Recovery
  6. Windows Boot Performance Diagnostics
  7. Understanding the Startup Process
  8. Power-on Self Test Phase
  9. Initial Startup Phase
  10. Initial Startup Phase for BIOS Computers
  11. Initial Startup Phase for EFI Computers
  12. Windows Boot Manager Phase
  13. Windows Boot Loader Phase
  14. Kernel Loading Phase
  15. Control Sets
  16. Values for the Start Registry Entry
  17. Value Descriptions for Type Entries
  18. Other Registry Entries in the Servicename Subkeys
  19. Session Manager
  20. Logon Phase
  21. Important Startup Files
  22. How to Configure Startup Settings
  23. How to Use the Startup And Recovery Dialog Box
  24. How to Use the System Configuration Tool
  25. How to Use BCDEdit
  26. How to Interpret BCDEdit Output
  27. How to Back Up and Restore Settings
  28. How to Change the Default Operating System Entry
  29. How to Change the Boot Menu Time-Out
  30. How to Change the Order of Boot Manager Menu Items
  31. How to Create an Entry for Another Operating System
  32. How to Remove a Boot Entry
  33. How to View and Update Global Debugger Settings
  34. How to Remove the Windows 7 Boot Loader
  35. How to Configure a User Account to Automatically Log On
  36. How to Disable the Windows Startup Sound
  37. How to Speed Up the Startup Process
  38. The Process of Troubleshooting Startup
  39. Startup Troubleshooting Before the Starting Windows Logo Appears
  40. How to Start the System Recovery Tools
  41. How to Run Startup Repair
  42. How to Use BootRec.exe
  43. How to Diagnose Hardware Problems
  44. How to Use System Restore
  45. How to Manually Repair the Boot Sector
  46. How to Manually Update the BCD Registry File
  47. How to Manually Replace Files
  48. How to Reinstall Windows
  49. Startup Troubleshooting After the Starting Windows Logo Appears
  50. How to Restore the Last Known Good Configuration
  51. How to Enable Boot Logging
  52. How to Start in Safe Mode
  53. How to Identify Failing Drivers and Services
  54. How to Analyze Startup Problems in Safe Mode
  55. Event Viewer (Eventvwr.msc)
  56. System Information
  57. Error Reporting Service
  58. How to Use Device Manager to View or Change Resources
  59. How to Analyze Boot Logs
  60. How to Roll Back Drivers
  61. How to Temporarily Disable a Service
  62. Troubleshooting Startup Problems After Logon
  63. How to Temporarily Disable Startup Applications and Processes
  64. How to Disable Startup Applications Using the Shift Key
  65. How to Disable Startup Programs Using the System Configuration Utility
  66. How to Disable Startup Applications Configured Using Group Policy or Logon Scripts
  67. How to Permanently Disable Startup Applications and Processes
  68. Manually Remove the Entry