I've got two external drives. I've tried them with two separate pieces of equipment (an external enclosure and a Universal Drive Adapter). The drives won't mount at all. Disk utility, DiskWarrior, and Data Rescue...none of them even recognize the drives. One of the drives is brand new. The other one, I got it mounted for about five minutes using the Drive Adapter, but then the drive disconnected and won't re-mount. Again, nothing even recognize the drives. I've tried via USB (with the Adapter) and FW400 and FW800 (with the external enclosure). So I'm stumped. I restarted my iMac thinking that might help. Doesn't, unfortunately. But I'm thinking it must be a software issue, since I know the drives are good, and I know I didn't lose USB AND both FWs all at the same time on the iMac. Anyone have a suggestion where I should go from here?