A new version of the File system API that provides discovery and restoration for deleted files in Windows Vista is available
The existing File system APIs in Windows Vista do not provide an easy way to discover and restore deleted files. A new version of the File system API is available that enables third-party developers to discover and restore deleted files from nonencrypted volumes by extending the File Management APIs.
This new API also lets developers pass a password or a recovery key file. Therefore, you can discover and restore deleted files from BitLocker-encrypted volumes. This API does not support the restoration of files from other kinds of encrypted volumes.
This API can only be used to extend the File Management APIs for Windows Vista. Additionally, these functions are only supported when you use the functions in an offline environment, such as Windows Preinstallation Environment (Windows PE) or Windows Recovery Environment (Windows RE).
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB943790.