Upgrade from Mountain Lion to Yosemite

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Upgrade from Mountain Lion to Yosemite

I Purchased a new iMac from the Apple Store in April of 2013. I believe it came with Mountain Lion installed and I never upgraded to mavericks but I was trying to upgrade to Yosemite today. Although my computer seemed perfectly fine before I tried to install, Something went wrong. It downloaded but would not complete the install. It told me that Yosemite can not be installed. As I went into disk utility and tried to figure out why, I noticed that Macintosh HD was greyed out. Also when I plugged in my external hd with my time machine backups on it, it saw the external but couldn't even find a drive to restore to. in a few places it seems like my Macintosh HD doesn't exist. Also in DU it says it is unmounted but I have no idea why. does anyone have any idea what happened or what I can do?

iMac (21.5-inch, Late 2012), OS X Mountain Lion (10.8.2), null

Posted on May 16, 2015 10:15 PM

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Answer 1

Paul_31

Level 6

14,160 points

May 17, 2015 12:26 AM in response to amateria7

Not sure what's caused the problem, but have you tried running Disk Utility from the Recovery HD to check the Macintosh HD for faults/repair?

Restart holding down Command + r, select Disk Utility: OS X: About OS X Recovery - Apple Support

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Answer 2

amateria7 Author

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May 17, 2015 12:39 AM in response to Paul_31

yes, that's what I've been doing. I didn't realize ctrl-r was called the recovery hd, but that's what I do. When I try to reinstall, there are no drives to select when it prompts me to select where I want to install it. And when I go to First Aid, it tells me it cannot be repaired and that I need to format and reCover the disk. I just don't understand how it went from being fine to completely destroyed. I feel like I am overlooking something simple that accidentally got knocked out of whack when I tried to install or something.

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Answer 3

Paul_31

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May 17, 2015 12:45 AM in response to amateria7

Will the Mac currently boot in 'Safe Mode'?

Disconnect any peripheral devices and restart holding down the 'shift' key until it boots. Input your admin password if prompted and let it complete the boot-up process (it will be slow to boot-up, assuming the Mac is actually bootable). Once booted try restarting normally from the Apple menu. Does the Mac boot? if so, go to the Apple menu>About this Mac - it should stay what version of OS X is installed, Post back your results.

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Answer 4

amateria7 Author

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May 17, 2015 12:48 AM in response to Paul_31

No. It starts to, but shuts off shortly after it shows the apple Boot up screen.

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Answer 5

Paul_31

Level 6

14,160 points

May 17, 2015 1:01 AM in response to amateria7

Prior to starting this process, did you make a complete and up-to-date backup that you can use to restore from? You may need it.

Have you tried booting into the Start-up manager? Restart holding down the Alt (Option) key and it will hopefully take you to a screen that displays your Macintosh HD. Select it (you may need to use the arrows on the keyboard to navigate to it if the mouse isn't functioning at this point) and hit the enter key to start the boot-up process. Any luck?

You may want to wait to see if anyone else has some other suggestions, but if the Recovery HD won't allow you to repair the HD or re-install a working version of OS X, you may need to resort to Internet Recovery (restart holding down Command + option + r) - this connects you to Apple's servers and should allow you to re-install a working OS.

To emphasise, I'd suggest waiting to see if any other contributors on here have any other suggestions you could try before going through the pain of erasing, re-installing, restoring your data - although, worst case, it may come to that.

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Answer 6

amateria7 Author

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May 17, 2015 1:37 AM in response to Paul_31

my last time machine back up was a year ago. 😟 When I restart holding the option key, it actually displayed Macintosh HD as a start up disk I could select. So I did and restarted, but it did the same thing it did when I first began installing Yosemite: it starts, tells me 24 minutes remaining, then 23, then it hangs and then 5 minutes later it tells me that "OS X CAN NOT BE INSTALLED ON YOURCOMPUTER, file system verify or repair failed. Quit the installer to restart your computer and try again"

AND this time when I do what it says, it prompts me to choose startup disk and the Mac HD is there but when I choose it, "startup Disk could not gather enough info on the selected disk"

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Answer 7

Paul_31

Level 6

14,160 points

May 17, 2015 2:28 AM in response to amateria7

Unfortunately it sounds like you're faced with having to go the Internet Recovery route, assuming you have first tried to re-install OS X using the Recovery HD (rather than Internet Recovery). Not good that you don't have a current backup, and hopefully, re-installing the OS will leave your data on the Macintosh HD undamaged. However, without reliable backup, prepare yourself for the worst.

I believe the Recovery HD will attempt to re-install the OS that was on the Mac just prior to your problems, whereas Internet Recovery will install a version of the OS that shipped with the Mac when new. Worth reading the detailed instructions from Apple in the link I first posted about your recovery options.

Here's a non-Apple article which may also help: http://osxdaily.com/2014/12/14/reinstall-os-x-mac-internet-recovery

Good luck.

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Answer 8

Eric Root

Level 10

684,033 points

May 17, 2015 7:55 AM in response to amateria7

Before trying to use Internet Recovery, try booting into the Recovery Partition, then open Disk Utility's Restore tab. Get an external drive with no data on it and use Disk Utility to copy your data to the external. This will give you the best hope of being able to recover your files since you don't have a current backup.

Then follow Paul's suggestion.

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Answer 9

amateria7 Author

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May 17, 2015 9:32 AM in response to amateria7

Thank you for all of your help. I realize this might be a dumb question but when you refer to my data, the data I'm going to select to move to the new external HD, I am assuming you mean to select "Macintosh HD" from the left panel in DU. However I'm wondering if it would make a difference if I selected the disk that is above Macintosh HD, the main internal disk. I am a little confused because it seems to me that with previous Macs, Macintosh HD was the top level internal disk rather than just bring a partition.

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Answer 10

amateria7 Author

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May 17, 2015 10:38 AM in response to Eric Root

OK, never mind about that question. I am now doing the Rrestore to an external HD partition. I had to create the partition so it would be GUID. And it says it is copying right now.

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Answer 11

amateria7 Author

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May 17, 2015 11:07 AM in response to amateria7

Crap. It failed. It was copying for about 20 minutes though. I wasn't sure about how I set up the partition and I chose Mac OS Extended Journaled for the destination partition format. Could that be the problem? I do not have any non-journaled options besides exFAT and free space. Do you think that might have caused the problem?

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Answer 12

Eric Root

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May 18, 2015 10:38 AM in response to amateria7

That is the correct format. If you are using the restore tab, it will reformat the drive as part of the copy process.

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Answer 13

amateria7 Author

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May 18, 2015 10:55 AM in response to Eric Root

I tried to Restore in Recovery mode a few times and it always tries for 20 or so minutes then fails with an "I/O" error. I'm guessing it might be the fact that Macintosh HD is now about 50MB bigger than what is available on my external, even though I've tried erasing everything off of the external several times. Both are supposed to be 1 TB. But I don't understand why the Macintosh HD is saying it is a full TB since I wasn't anywhere near maxing out the storage capacity.

I wanted to see if there was some way to go into Terminal to delete files, but I'm not sure that is a good idea since I can't even understand why it is saying there is so much data in the first place.

I don't know what to do.

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Answer 14

Eric Root

Level 10

684,033 points

May 19, 2015 8:02 AM in response to amateria7

I/O errors usually indicate the drive is failing. Take the computer and the external with you.

If you live near an Apple Store, make a Genius Bar appointment to have the computer tested. Supposedly there is no charge for testing. Use 2nd link if not near an Apple Store or aren’t in the US. Hardware Repair - Keeping Confidential Data Safe

Genius Bar Reservation US

Authorized Service Provider

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