2012 iMac, fusion drive. Had a Porsche LaCie drive partitioned to Time Machine and the other half for Carbon Copy Cloner. All of a sudden today it won't recognize the drive. It is running, makes the usual boot up sound when it starts up, but isn't seen by the computer....except if you go to the USB device tree. It shows up there, both partitions, but won't show up as a connected drive in Finder or on the desktop. Another thing....if it is connected and running, Disk Utility won't open; it's looking for drives. As soon as I turn it off, the utility opens. It also doesn't show up on my wife's iMac so my assumption is the drive is hosed in some way. Meanwhile I have no Time Machine. I've tried different USB ports, rebooting the iMac....is there anything I am missing? And why is it showing up, with all the information, on the USB device tree if it is not recognized??