iMac 2012 Booting to OS X Utilities & Macintosh HD missing

[CalumCJL]

I am having a rather big problem. I have a iMac 2012 with a fusion hard drive.

When I boot up the iMac it plays the chime but then loads straight to OS X Utilities. I am then given the 4 options pictured. I have tried everything.

This problem occured when recently (since Monday after I installed a OS X update) when I have gone to shut down my computer, it closes all open apps but then just sits there, forcing me to press and hold the power button to power off. This was getting annoying so today I decided I would try to restore from a Time Machine back up. I went to restore and it failed. I then went to reinstall OS X and realised that Machintosh HD is no longer even listed. (It is also no longer listed when selecting a drive to restore a time machine back up to).

Weirdly, bootcamp running Windows 8 on the iMac seems to be working fine and I am writting this now on there. I have attached some pictures to show more of what I mean as I may not be explaining myself correctly.

I should add that bootcamp is a partition of my Machintosh HD so it makes me think (and hope) that the Hard Drive is not completely dead?

 

[jbarley]

What happens when you are booted into "Utilities" and then choose "Disk Utility".
Does the Macintosh partition show up there, so maybe you can run disk repair on it?

 

[CalumCJL]

What happens when you are booted into "Utilities" and then choose "Disk Utility".
Does the Macintosh partition show up there, so maybe you can run disk repair on it?

Thanks for the reply. Unfortunately the Macintosh partition doesn't seem to appear unless I am overlooking something? I added a picture of the options I have in Disk Utility.

 

[DeltaMac]

You have a fusion drive, which is two separate devices, joined into one virtual device.
One device is an SSD, and the other is a hard drive.
Looks like your Fusion Drive is partly gone, and the SSD device is the part that is missing.
The Boot Camp partition remains, as it is not on the SSD drive at all - only on the hard drive.

This might be a good time to try out Disk Warrior.

 

[CalumCJL]

You have a fusion drive, which is two separate devices, joined into one virtual device.
One device is an SSD, and the other is a hard drive.
Looks like your Fusion Drive is partly gone, and the SSD device is the part that is missing.
The Boot Camp partition remains, as it is not on the SSD drive at all - only on the hard drive.

This might be a good time to try out Disk Warrior.

Thanks, I will check out to see what Disk Warrior is. Is there a way to get the iMac to just use the notmal Hard Drive and ignore the SSD? Just for the time being at least.

 

[DeltaMac]

You can revert the corestorage volume (the combined volume that uses both the SSD and the HDD)
http://www.chanhvuong.com/2568/revert-mac-os-x-yosemite-core-storage-back-to-mac-os-extended-hfs/

However, if the SSD is dead, then there may be no effective way to do that simple reversion. If we assume that the SSD is dead, then you have lost that portion of the fusion drive, which includes the system software, and probably all your apps.
If you have a good backup of your OS X drive, using Time Machine, or one of the third-party backup utilities, then all you need to do is run the corestorage revert command, and then erase your hard drive, then restore the OS X volume using your backup. You would also likely lose the boot camp volume, too. You would need a backup of your windows partition, too. It would be easy, as you can still boot to the boot camp partition, as it is apparently not affected.
(Because of that, you MAY be able to do the revert without touching the Boot Camp partition - I am not sure about that...)

If the SSD is dead - then you may be able to ignore it until you replace it, then you can restore the Fusion drive (more fun with that, too )

 

[CalumCJL]

If it comes to replacing it, do I replace just the SSD? Or do I replace the whole thing with a Hybrid Drive? Like this one; https://www.amazon.co.uk/Seagate-Se...00FQH7MQ2/ref=cm_cr_arp_d_product_top?ie=UTF8

Sorry I am pretty clueless, this will be my first apple repair.

 

[jbarley]

From the looks of that Disk Utility Screen shot I'd say this thread belongs in the El-Capitan forum.

 

[CalumCJL]

From the looks of that Disk Utility Screen shot I'd say this thread belongs in the El-Capitan forum.

Yes sorry, just realised I did post in the wrong section. Is it possible for mods to move it please.

 

[grahamperrin]

You can use Terminal in Recovery OS to tell whether a device is no longer detectable. This simple command:

diskutil list

Copy the output from that command, quit Terminal, then use Safari in Recovery OS to paste the output to this topic.

If part of the Fusion Drive hardware has effectively disappeared then I should probably have no hope of reusing the file system. (You might use something to scavenge for files, but the results would be disorderly (not in a user-friendly hierarchy of folders), that type of thing.)