Start up problem

[Awheeler]

My daughters 2010 iMac (has been running Yosemite for a couple of weeks) froze today, so she turned it off. It now won't restart (gets stuck at apple logo on white screen and loading bar and then turns itself off).

When I cmd r to OX Utilities is says the macintosh HD is not mounted. Does this sound like the HD drive is dead, or do you have any ideas of how to fix? Or do you think I need a Genius Bar appointment??!? Thanks!

 

[honestone]

From what you said, you used Command-R on start-up, which normally boots "directly" to the (invisible) Recovery HD partition. Sometimes, that does not get installed with the OS installation, but not being able to boot at all is definitely an issue. You could try just holding down the Option key while your Mac is starting up, to see if you get a list of start-up volumes. But, things don't sound that great.

Do you happen to have an external disk? If you do, and your Mac is working fine, you can use the free version of SuperDuper! to make a bootable backup (actually, clone) of the system on your Mac (you can get SuperDuper! from here: http://www.macupdate.com/app/mac/13803/superduper). Once you make that backup, attach that hard disk to your daughter's iMac, boot it up holding down the Option key, and (hopefully) you'll see that partition on the external drive. You can then select it, and boot your iMac from there. You can use Disk Utility to analyze the drive on the iMac.