Windows

Modifying the Windows 7 boot loader with the Boot Configuration Data Editor tool

In Windows Vista and later versions of Windows, the bootloader was moved from boot.ini to a utility called BCDEdit. Derek Schauland shows you how to modify the boot config data with the new tool.

Sometimes dual-booting a system is a handy way to test new software, a new operating system, or an application that needs to be run in a specific version of Windows. Other reasons to dual-boot might include replication of a client environment.

Windows handles dual-booting by using boot.ini to display a menu of bootable choices or partitions found on the current system. In Windows Vista and later versions of Windows, the bootloader was moved from boot.ini to a utility called BCDEdit.

Recently, I decided I could make better use of some disk space that I had set aside to create a bootable VHD for Windows Server 2008 R2. There was no data other than the OS installation contained within the file because I had used it only to prepare a blog post about booting from Virtual Hard Disks. To free up the space, I deleted the VHD.

Note: Always make sure to back up any data that you want to keep before deleting or modifying partitions on VHDs. Your changes could make the partition unbootable.

Once I had the VHD removed, I thought Windows would be smart enough to clean up the boot loader, but I was not so lucky. I had Windows 7 set as the primary OS, so I was not without a system.

I started looking around for boot.ini and was directed toward the Boot Configuration Data Editor (BCDEdit) as the utility to use when editing boot loader information in Windows 7 (and in Vista too).

To begin, open the Start menu, select All Programs, and then choose Accessories. Right-click on Command Prompt and select Run As Administrator. Once in the command window, type bcdedit. This will return the current running configuration of your boot loader, showing any and all items that can boot on this system.

In this example, I decided to remove the entry for my Windows 2008 R2 installation, as I wouldn't need it for the time being. To remove an entry, you will need to know the Boot Loader Identifier (found in curly braces in Figure A). Figure A

I copied the whole list into Notepad and then selected and copied just the ID, braces included.

Removing an entry from the Boot Loader

One simple command got the Windows Server 2008 R2 entry out of the boot loader. At the command prompt, enter the following:

Bcdedit /delete {boot loader identifier}

Press Enter, and the Boot Configuration Data Editor (BCDEdit) will remove the entry for the ID you specified and display a message when finished. When Windows starts, the only choice available in the boot menu should be the current Windows installation.

Warning: Be careful when editing the boot configuration data. If you mistakenly remove the current instance of Windows, you may render your computer unbootable.

About

Derek Schauland has been tinkering with Windows systems since 1997. He has supported Windows NT 4, worked phone support for an ISP, and is currently the IT Manager for a manufacturing company in Wisconsin.

1 comments
boyans
boyans

Novice and advanced users do not have to go to command line and use bcdedit anymore. Visual BCD Editor is a free GUI tool to allow complete editing of Windows 7 BCD. Boot loaders for Windows XP and later are created automatically (if missing) so your dual or multi boot system is created on click. And the dual boot repair functionality comes handy when things go wrong. Tool site - http://boyans.net