The operating system rescue disk can be useful when an encrypted hard drive cannot be accessed for some reason and the operating system cannot load.
You can load an image of the Windows operating system using the rescue disk and restore access to the encrypted hard drive using Restore Utility included in the operating system image.
To create an operating system rescue disk:
Refer to Microsoft help files for instructions on creating a custom image of the Windows pre-boot environment (for example, in the Microsoft TechNet resource).