Windows 7 / Getting Started

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How to Create an Entry for Another Operating System

You can use BCDEdit to create an entry for an operating system other than Windows 7. You may need to add boot entries to the BCD registry file if you want to be able to load different operating systems on a single computer. Although Windows automatically creates boot entries for existing operating systems when installed, you might need to add a boot entry manually if you install another operating system after Windows 7 or if you want to load an operating system from a newly attached hard disk.

By default, the BCD registry file contains an entry called {ntldr} that is configured to start an older version of Windows from your C:\ partition. If you have only one older operating system and Earlier Version Of Windows does not currently appear on the computer's boot menu, you can use this existing entry to start the older operating system. To do this, call BCDEdit /set to configure the boot volume. Then add the entry to the Windows Boot Manager operating system menu by calling the BCDEdit /displayorder command. The following code demonstrates how to do this.

REM Modify the following line to identify the other OS' partition
REM The following line could also be, "bcdedit /set {ntldr} device boot"
bcdedit /set {ntldr} device partition=C:

REM The following line makes the entry bootable by adding it to the menu
bcdedit /displayorder {ntldr} /addlast

You can verify that the new entry will appear on the boot menu by running the command bcdedit /enum ACTIVE and looking for the Windows Legacy OS Loader entry.

If you need to be able to choose from multiple older Windows operating systems, you should choose the {ntldr} entry from the boot menu. The Windows Boot Manager will then pass control to Ntldr, which will display a menu based on the Boot.ini file that you can use to choose from all Windows operating systems.

If you want to create an entry for a non-Microsoft operating system, you can either create an entry using the bcdedit /create command, or you can copy the existing {ntldr} entry and update it for the operating system. To base a new entry on {ntldr}, copy the entry, update the boot loader path, and then add it to the boot menu by running these commands.

bcdedit /copy {ntldr} /d "Other operating system (or other description)"

REM The previous command will display a new GUID that identifies the copy.
REM Use the GUID in the following command, and modify the partition identifier as needed.
bcdedit /set {NEW-GUID} device partition=C:

Note Don't retype the GUID by hand-you're likely to make a mistake. Instead, copy it to the Clipboard as follows: Click the command menu in the upper-left corner of the command prompt window, click Edit, and then click Mark. Select the GUID text (including the brackets) and then press Enter on your keyboard. To paste the GUID to the command prompt, click the command menu, click Edit, and then click Paste.

Now run the following command to identify the operating system's boot loader.

REM Replace the last parameter with the boot loader filename
bcdedit /set {NEW-GUID} path \boot-loader

If {ntldr} was not part of the boot menu when you copied it, you also need to run the following command to add the copied entry to the boot menu.

bcdedit /displayorder {NEW-GUID} /addlast

Additionally, you might need to configure the operating system's own boot loader.