I continued to have the same problem and eventually moved all the data off the drive and decided to just use it as a (probably unreliable) backup. To be clear, I have 7 drives plus a system disk on this machine. 3 + system are internal connected via SATA and four are external all via USB. I have two 1TB externals that have had no problems and an older WD 250GB that doesn't have the problem. None of the internals - all WD - have had the problem either. I suppose it's conceivable that it's mobo related but it seems rather unlikely. Further, it appears that johno7 is running a Seagate (?) so it's happening across manufacturers. Can't wait to see this thread light up on October 23rd.