TechnoDino

Trying to recover data from a Western Digital drive (WD Caviar; SATA; 160 G). I have set recuva to check for undeleted files. The drive is recognized by Windows 8.1. Recuva scans one drive fine. When it tries to scan the drive I am trying to recover, the following error: HarddiskVolume 3: unable to determine file system type and stops. File system is NTFS. I'm open to suggestions. John