FYI, I just got the 1.5TB model in the mail and it is thicker than 12.5mm. It will not fit comfortably inside my 17" MBP unibody. I can get the case to screw shut, but even with the stabilizing screws on the hard drive removed, the case will not fully close there. I may leave it anyway, since the case at least screws shut, but this is not the elegant solution that the WD 1TB was.