I'd test that before I'd blame the DNS-323. FWIW, I did that exact thing to make sure the RAID would rebuild when I installed my 1.5TB Samsung drives, I pulled one, took it and formatted it with the hard disk diagnostic, then stuck it back in to see if it would rebuild. With Firmware 1.07 it rebuild without any issues. I had previously tested both of the drives after receiving them before trying to use them in the DNS-323.