Can I use EFS with BitLocker?
Yes, you can use Encrypting File System (EFS) to encrypt files on a BitLocker-protected drive. BitLocker helps protect the entire operating system drive against offline attacks, whereas EFS can provide additional user-based file level encryption for security separation between multiple users of the same computer. You can also use EFS in Windows 7 to encrypt files on other drives that are not encrypted by BitLocker. The root secrets of EFS are stored by default on the operating system drive; therefore, if BitLocker is enabled for the operating system drive, data that is encrypted by EFS on other drives is also indirectly protected by BitLocker.