OK. So my 3TB Fusion drive has stopped responding on my iMac 27" late 2012(details below). I reinstalled ML 10.8.3 on my external 2TB WD USB 3 drive, and I boot from there. It works just fine but not as fast as with SSD drive. Also installed Parallels 8 and Windows 7 Home Premium. When I open Disk Utility, I see the Fusion drive grayed out. It's impossible to perform anything on that drive: partition/format - NOTHING!! When I open system report, and serial-ATA I see the Fusion drive, divided to the Samsung 128GB SSD drive(BSD Name: disk 2), and the 3TB HD drive(BSD Name: disk 0). My question is: How can I format the Fusion drive so that I can reinstall ML on it once again?