I have a new 2TB La Cie b/u drive which, when plugged into my 27" iMac, prevents it from booting. Turning the drive on & off during the boot process fixes the problem. It is as if it is sleeping and won't automatically awaken.
I exchanged it for a new drive and it does the same thing. OS10.6.7, brand new d2 Quadra 2TB La Cie External drive.
