Ok, this has turned out to be a tough one. I have a 4TB external WD USB hard drive. It works fine, and mounts fine, on every machine I have, including my Mac, except for ONE. I can't figure it. It simply will not mount or show up on my main workstation. It won't even show up in the Drive Manager, nor can I manage it in Diskpart. It simply will not show up at all on this machine. And before you little brainiacs recommend it, I have already used Diskpart to flush all remembered USB Hard Drive letters from the registry. I beat you to it Still no mount. I'm baffled. The drive is obviously fine because it works on all other machines. Any idea's ?