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Disk Utility won't mount a disk

I have a 1TB HDD that was in a backup system that I'm sending in to the vendor for replacement. I am trying to mount it in an external enclosure but DU won't recognize it. When I first plugged it in, DU mounted it fine (it was 1TB of a 2TB sparse bundle) and I did a simple erase. When I swapped it out for the other HDD and then swapped it back, DU will no longer mount it. In fact, DU doesn't show a darn thing except the expected boot volume. I've disconnected, reconnected, powered it off then on, but nothing happens.


I'm on 10.8.2 using Disk Utility version 13 (444) on a late 2012 Mac mini.


Is there a way of "forcing" it to mount? Is there a CLI in Terminal that will mount it? Is there a 3rd party app that will do this (it's been ages since I last used something like Disk Warrior!)?


I really need to do a secure erase before sending it back.


Thanks!


-Tod

Mac mini, OS X Mountain Lion (10.8.2), 10GB SDRAM 240GB SSD & 500GB HDD

Posted on Mar 7, 2013 8:09 PM

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15 replies

Mar 7, 2013 8:44 PM in response to TodFromIndiana

I would start with the basics. First, what is the external enclosure, firewire or USB? Did you check if there is a firmware update for the enclosure itself? I had this problem with a My Book II enclosure from Western Digital and updated the firmware then the disk finally mounted. If that is not a problem, do you have another hard drive you can try in the enclosure to rule it out as the culprit? or another enclosure or computer to try it out on?


Then once you know with 100% certainty that the external enclosue is fine, you can try Disk Warrior which does sometimes mount disks that DU won't see. Tech Tool Pro and Data Rescue are also sometime good with these issues.

Mar 8, 2013 12:53 PM in response to Alan Wood

@Alan Wood: Thanks. I neglected to mention that I moved the external enclosure (It's one of those things from OWC where you can slip a drive in or out for testing/formatting purposes) to another Mac and it worked fine. I can't use that Mac for more than a few minutes at a time. I appreciate your tips about DW and TTP. I have old licenses so I'll probably hve to pay an upgrade price.


-Tod

Aug 8, 2015 5:28 AM in response to macjack

Hi Tod, I'm trying your advise but please correct if I'm doing wrong Macbook pro with upgraded Yosemite): I connect my WD passport studio with firewire (that does not mount or show in Disk Utilities), and use your CLI command but what do you mean with (number if disk)? I tried all the numbers on mine but does not work. It keep on saying: You must specify a filesystem type with -t.

Please help?


Cheers

Marius

Aug 13, 2015 4:34 PM in response to TodFromIndiana

Very similar problem. Bought a used mid 2010 Macbook Pro 13 inch that would not recognize internal HD. I swapped the internal cable from my working 2009 MBP 13 inch and, BINGO, everything works! Too bad the cable is $50 since it also carries the IR sensor signal and lamp.


Its odd that such a cable would "fail" - maybe its the circuit board connector?

Apr 26, 2016 2:30 AM in response to TodFromIndiana

Hi, I have exactly same problem, my hard drive Transcend 2TB is working perfectly on windows. On mac, i have a Macbook Pro and a Macbook 12 in brand new. First time i connect it worked fine, but now its random. Sometimes i can take up to have an hour of rebooting to get my HDD running. It powers up but not recognised. Both Macbook pro and Macbook same behaviour. Read something about reseting the PRAM, using the keys: COMMAND+OPT+P+R at the same time when rebooting it also works randomly. Very frustrating. Looked for the drivers update of the HDD no luck. Used the DISKUTIL DISK command on the terminal. It does not list it. Not working. Also, called Apple support, they mentioned that it was the HDD Format, so suggested MAC OS X Extended format. So took a day work. Worked the first time connected , now random. Frustrating.

Please, useful advices???

Disk Utility won't mount a disk

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