So I have been successfully running a DIY fusion drive for a few months when the sad suddenly died. I knew this because when I booted the apple screen would turn into a cancel sign. So I booted from a recovery USB, and used terminal to undo the fusion setup with diskutil ca delete <fusion drive number>. I then removed both hard drives, reinstalled my SuperDrive and left only my 500gb hdd. I attempted to boot back into USB and use disk utility to format the hd to hfs. Every time I try, it fails to unmoving the drive and will not let me proceed. I then think, ok both drives are dead. So I try 3 other know working drives. All of those drives aren't even seen in disk utility, only the one that was once part of the fusion drive. I then put that drive in a windows computer, set GUID partition table and format to NTFS and am able to read/write to the drive. I put it back into my MacBook to reformat and it does the same thing. Any advice?