Just found out about this:
http://seagate.custkb.com/seagate/cr...p?DocId=207931
I have 2 drives affected by this, and I'm waiting for the results for the last one to be validated.Welcome, Seagate hard drive owners. A number of Seagate hard drives from the following families may become inaccessible when the host system is powered on:[FONT=Arial,Verdana,sans-serif] Barracuda 7200.11
DiamondMax 22
Barracuda ES.2 SATA
Once a drive has become affected the data becomes inaccessible to users but the data is not deleted. Seagate has isolated this issue to a firmware bug affecting drives from these families manufactured in December 2008.
Please use the following tools and instructions to determine if you have one of the affected products. If your drive is affected, we recommend that you update the firmware on the disk drive to prevent this condition