BCD is the boot configuration data in every Windows computer that contains critical data to help properly boot into Windows. BCD entries usually contain the MBR and system disk drive information so that bootloader can initiate the booting of Windows. With a corrupt or invalid BCD, you will not be able to boot into Windows at all. This is why it makes sense to create a backup of your working BCD entries. This is specially useful if you are going to install any other operating system like Puppy Linux in the dual boot mode installation and which can make a mess of your BCD entries.
You can backup and restore your BCD settings in two different ways – using the command line interface (CLI) and using EasyBCD tool. In fact they both use the same technique but the second method has a GUI. In the first method, you have to open an elevated command prompt and give the following command:
Obviously, you have to change the file d:\backup\001.bcd to wherever you want to store the backup file. You will see a message that the operation was completed successfully. The restoration process is very similar except in that case, you use the command with the /import parameter like this:
In the second method, EasyBCD Community Edition can be used. You have to download and install EasyBCD community edition in Windows. Then launch EasyBCD, select the BCD Backup/Repair and then you can choose to backup the BCD settings by choosing a file location and then clicking on the Backup Settings. In case you want to restore the BCD settings, you can choose a backup file and then click on the Restore Settings.
If your Windows PC is not able to boot because of corrupt BCD, then you will have to use a Windows installation disk to boot into the PC. On the Windows install screen, choose the recover your PC option and then choose a startup repair to create a basic BCD so that you can boot into Windows. Once you are into Windows, then you can restore the original BCD from the backup.
You can download EasyBCD Community Edition from http://www.softpedia.com/get/System/OS-Enhancements/EasyBCD.shtml.