Hi guys Bought a new iMac just over 5 months ago. It's the latest iMac with the 780M 4GB GPU and a 1TB HDD. Today when I turned it on, I got the following: The apple logo (on grey screen) Spinning progress thing underneath logo grey horizontal progress bar When the grey progress bar reaches full width, the iMac turns itself back off. I booted into the recovery partition and here are the results of some checks Disk Utility > Verify Disk > Macintosh HD (in red) Incorrect number of thread records (in red) The colume Macintosh HD was found corrupt and needs to be repaired (in red) This disk needs to be repaired. Click Repair Disk Repair Disk Error: Disk cant be repaired. Back up as many files as possible, reformat the disk and backup your files. Install OSX When I choose this option, the only available partitions showing are Bootcamp and Recovery partiitions. The OSX HDD partition isn't showing. Obviously this looks like a fatal HDD failure, right? Whats suprising to me is the HDD failure on a machine thats rarely used. I've been meaning to port across all my Macbook files since I bought it 5 months ago so the OSX partition has only been booted up and used a few times (literally). It's actually been serving as a second monitor for the past few months and in the evenings I play BF4 on BootCamp.