Check to make sure your HDD has the correct Master setting, if you are only using one, it should display it in the Primary Master, if it has a jumper on the HDD, using the manual, make sure it's on the correct pin setting.
It can vary with different brands. Best to check your manufacturer website for the specifics (the actual HDD itself might also tell you). If you look at the back of the drive, near the eSATA cable input, there should be about 8 pins that have a plastic piece on it, that piece is the jumper, and then match the jumpers location to the Primary Master that is displayed on manual/HDD