That is not always true and I am surprised that as a moderator you are saying this. I had an internal drive failing a DST and after running SeaTools for DOS and having it find and repair a couple of bad sectors, the drive passes the DST test. In fact, the Seagate site specifically says to run it before requesting an RMA to replace a drive.
It could be that the drive in question really does need to be replaced but it's certainly worth a shot at running the DOS version to try to fix the problem.
