How to Backup Encrypted File System (EFS) Certificate in Vista, Windows 7, and Windows 8
If you encrypt data (files and folders) on your computer, then you need a way to recover that data in case something happens to the encryption key. If your encryption key is lost or damaged and you don't have a way to recover your data, the data is lost. To make sure you can always access your encrypted data, you should back up your encryption certificate and key.
The Encrypt feature is only available in the Vista Business, Ultimate, Enterprise, Windows 7 Professional, Ultimate, Enterprise, and Windows 8 Pro and Enterprise editions.Be sure to store the backup (Exported) copy of your EFS certificate in a safe place. You will need it if you have to...