WD Black 4TB on Mac Pro 2008


I just bought two WD Black 4TB drives to replace 2 Seagate Barracuda 2TBs on my early 2008 Mac Pro (3,1). The drives are not seen by the system - totally invisible. As far as I know they should be compatible. I have a 1TB WD Black in the 4th bay, and an OWC SSD in the first. I’ve tried swapping bays around, the 1TB WD Black always shows up, the 4TBs do not.

Also tried hooking up one with a SATA cable to USB on a Mac Air laptop. The drive spins up, but is not detected.

It seems unlikely that two new, sealed WD drives from a reputable retailer are defective, but I can’t think of any other reason.

Can anybody tell me if there is some incompatibility ? According to the OWC website in the USA, they sell / recommend these drives for this model of Mac Pro…

Thanks for any advice



Have you check on the disk utilities to see if the drive are showing there. If they are new drives, they might need to be formatted.