How do I reinstall things to normal on an erased iMac HD

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Level 1

27 points

How do I reinstall things to normal on an erased iMac HD

Hi All,

I think I have shot myself in the foot. For reasons I won't bore you with I decided to erase my iMac HD. Had to use terminal commands because disc utility can't cope with fusion drives. Having successfully erased the HD I then set about reinstalling the O/S and failed dismally. Having searched the 'net for a method the closest I could get is shown in the pic below. Disc Utility admits that there is a 3T HD is there but it does not appear on the desktop Try as as I can I cannot restore the Fusion drive. Everything in the disc utility drive is "greyed out". I have spent several hours looking for a method that will restore the Fusion drive.

The method I used to erase the drive can be found here :-

http://macs.about.com/od/diyguidesprojects/ss/Split-Your-Fusion-Drive-Apart.htm# step1

One of the methods which I was trying to use to restore the drive can be found here:-

Unable to format/partition hard drive

The above methods relies on me being able to use disc utility.

Any suggestions will be much appreciated. Fortunately i have several backup discs and a Laptop that i can use until the iMac problem is solved.

Thanks in advance guys :-)

UD

Posted on Aug 29, 2015 3:47 AM

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Answer 1

Rudegar

Level 10

170,748 points

Aug 29, 2015 5:02 AM in response to ugly__dog

you can restore it from the time machine backup

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Answer 2

ugly__dog Author

Level 1

27 points

Aug 29, 2015 5:46 AM in response to Rudegar

THNX Rudegar,

But I have never used Time Machine I have always used cloned backups or reinstalled everything from the clone. I've used Migration Assistant a couple of times. When I think about it when I got the iMac I cloned directly onto it from a backup disc almost as soon as I had put all my registration details in. I have never seen a virgin disc utility from an iMac. First stop on Monday will be to JB HIFI to have a look at one.

Cheers.

UD

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Answer 3

Aug 29, 2015 6:53 AM in response to ugly__dog

Have you tried using Internet Recovery ? I believe it became available w/mid 2011 iMacs and Lion. You simply need a functional hard drive (empty or corrupt) and a functioning Internet connection.

Internet Recovery calls out to an Apple server and downloads and installs the original version of OS X that came with your machine. IR will handle erasing and re-partitioning your HDD correctly for you. You can then upgrade OS X to your current version once you're back up and running.

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Answer 4

ugly__dog Author

Level 1

27 points

Aug 29, 2015 7:33 AM in response to blackdogaudio

Hi Blackdog,

Thanks for your input. I have tried Internet recovery. When it gets to the point where i have to pick which HD i want to install the O/S on I am not presented with any choices. Apart from Disc Utility nothing seems to be capable of detecting the HD. Disc Utility will detect it as shown in the pic I posted earlier but it just sits there dormant. I suspect that the problem is with the HD is a (former) fusion disc and I have to find my way around that.

I might leave it for a day or twe and let the dust settle

Thanks again Blackdog

UD

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Answer 5

Aug 29, 2015 7:35 AM in response to ugly__dog

Can you tell us the specific model iMac and the original OS version that was installed at the factory? And did the fusion drive come with this machine or is it an aftermarket modification you've made?

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Answer 6

rkaufmann87

Level 10

140,550 points

Aug 29, 2015 7:49 AM in response to ugly__dog

ugly__dog wrote:

THNX Rudegar,

But I have never used Time Machine I have always used cloned backups or reinstalled everything from the clone. I've used Migration Assistant a couple of times. When I think about it when I got the iMac I cloned directly onto it from a backup disc almost as soon as I had put all my registration details in. I have never seen a virgin disc utility from an iMac. First stop on Monday will be to JB HIFI to have a look at one.

Cheers.

UD

Then it should be simple, boot from the cloned HD and use the app;s restore function. You did not state which app you use to create your clone, it's either going to be SuperDuper or CarbonCopyCloner.

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Answer 7

Aug 29, 2015 7:58 AM in response to ugly__dog

EDIT: Just saw Rudegar's post - try his suggestions first!

If all else fails and assuming you don't have a hardware failure....here's a link for installing OS X to an external drive (flash drive, etc) so you can try to reformat the internal fusion drive again from a working version of DU and download/reinstall OS X from the App Store>Purchased tab assuming DU now recognizes your fusion drive when mounted from the external drive:

How to install OS X on an external drive connected to your Mac - Apple Support

I'll keep an eye on this thread...

regards,

Dave

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Answer 8

ugly__dog Author

Level 1

27 points

Aug 29, 2015 8:06 AM in response to blackdogaudio

Hi Blackdog,

The short answer is not much. I ordered it from the Apple Online store with the 3T fusion drive in it when it arrived. iI is a 27-inch iMac with Retina 5k Display.

It will be the last computer that i buy so i maxed out with everything. 32g Ram, upgraded the processor and the graphics card.

It was ordered on 22 June 2015. If it could find the HD Internet Recovery would install OS 10.10.

When I got it I booted it up and enterred my own details to get it running. I then cloned from one of the backup discs i had for the laptop i am using now. I got it about 10 days before the iMac. It was up and running in no time, i loved it. Given that I have never seen the iMac HD in its native state with Disc Utility I have decided that i will go into one of the Apple retailers on Monday and have a look at one and see if it is different.

I have several unused external HDs and i may make a Time Machine disc with one of them. I tried Migration Assistant and had the same problem.

There you have it Black dog

Cheers

UD

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Answer 9

ugly__dog Author

Level 1

27 points

Aug 29, 2015 8:09 AM in response to rkaufmann87

Hi rkaufman,

It is SuperDuper. I will try it but SuperDuper couldn't detect the HD either.

Thanks rkaufman.

Cheers

UD

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Answer 10

Aug 29, 2015 8:16 AM in response to ugly__dog

I've got a new, late 2014 5K iMac myself and blew the recovery drive myself experimenting a few months back testing disaster recovery....Internet Recovery restored my system without a hitch though! I'm running out for a while but will check back later. Hopefully someone will post a working solution!

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Answer 11

Aug 29, 2015 8:23 AM in response to ugly__dog

In your image you see that the Macintosh HD name has a rex X next to it. This indicates that there was a fusion drive that is no longer associated. You can either recreate the fusion drive using Terminal

http://macs.about.com/od/diyguidesprojects/ss/Setting-Up-A-Fusion-Drive-On-Your- Current-Mac.htm

or boot into the Recovery HD volume, run Disk Utility (not the OS X Installer), which will offer to fix the Fusion drive.

Tom

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Answer 12

ugly__dog Author

Level 1

27 points

Aug 29, 2015 8:36 AM in response to Tom Nelson1

Thanks Tom,

Bad news I'm afraid. I put that X there myself to draw attention to the fact that the HD existed.

I will certainly give your link a serious look tomorro. I'm Hutton' the sack :-)

Cheers Tom

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Answer 13

ugly__dog Author

Level 1

27 points

Sep 1, 2015 8:05 AM in response to ugly__dog

HI All,

The battle is over and the war has been won :-)

Thank you all for your efforts on my behalf?

THIS WORKS

http://www.wiredbob.com/2013/12/clean-installation-of-fusion-drive.html?m=1

For my particular issue I scrolled down the the part that says; Do this -

The iMac has the O/S reinstalled and in that limited environment everything is working perfectly. I did switch iCloud on so I could check the Bookmarks on my browser, my Contacts and the Calendar. Reinstalling the data can wait until tomorrow.

Thanks again for all your efforts guys.

UD

I don't know why the link won't link to the site directly. I cut and pasted it into the browser and the page loaded okay.

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Answer 14

Sep 1, 2015 2:46 PM in response to ugly__dog

Great news UD and thanks for sharing the fix!

Dave

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