Internal hard drive "gone"

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Level 1

43 points

Internal hard drive "gone"

I was trying to completely erase a 1000 GB drive partitioned into two 500 GB volumes. Disk Utility was having trouble erasing, so I went to Terminal and ran diskUtil commands. I tried to erase the disk, but got a failure message about ten minutes later saying that the disk wasn't configured. At that point, the disk "disappeared" from the Finder, Disk Utility, and diskUtil list. (It was previously listed as disk2, and that "slot" is empty. diskUtil commands on disk2 result in the message "Unable to find disk for disk2".

My other three internal hard drives and an external drive are happily spinning and work fine. I'd rather not trash the disk, though everything on it is backed up. Any ideas on how to "find" disk2? (I have another Mac Pro and can easily remove disk2 and put it in my other Mac, if that will help.)

Mac Pro, macOS 10.12

Posted on May 31, 2019 8:59 AM

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Answer 1

Top-ranking reply

iTBotB Author

Level 1

43 points

Jun 1, 2019 3:32 PM in response to HWTech

As I said, the disk was disk2. After whatever problem that occurred while erasing the disk, it didn't show up in disk list, but the disk2 slot was empty. One of the other three disks should have become disk2. So, it's weird.

DriveDx doesn't see the problem disk.

As suggested in a different post, the disk may be bad and failed the erase action. I'll try it in a different computer (that can run Snow Leopard with its superior Disk Utility) and toss the disk if I can't mount it. I made a clone and a data backup, so I won't lose anything.

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Answer 2

Jun 1, 2019 7:43 AM in response to iTBotB

iTBotb wrote:

I had a utility that could format a completely blank disk.

And you do today as well. Its name is Disk Utility. However -- the default View for Disk Utility is the completely useless Volume-View. and you have no Volume on that drive.

you need to change to Device View to see the raw devices by immutable Hardware-names:

.

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Answer 3

Eau Rouge

Level 8

42,602 points

May 31, 2019 9:36 AM in response to iTBotB

If you restart your Mac with disk2 still inserted do you get the 'This disk is unreadable' or similar dialogue with an Ignore, Initialise choice, if you choose initialise it should take you to Disk Utility where you can select Erase and then reformat the drive.

You can also try this on your other MacPro.

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Answer 4

May 31, 2019 4:36 PM in response to iTBotB

disk designations such as disk2 are re-computed each time you restart. do not assume it stays the same across a restart.

If just using Terminal commands, be sure to do a

diskutil list

to the be sure of which disk is which.

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Answer 5

iTBotB Author

Level 1

43 points

Jun 1, 2019 5:41 AM in response to Grant Bennet-Alder

Thank you for your reply. I know about disk designations, and I always check with "diskutil list." I found it strange the the disk2 spot was empty. If the Mac truly could not see that disk, a different disk should have become disk2.

I think that the mucked-up disk will have to be treated as a disk with no formatting: no GUID, FAT32, whatever. A long time ago (probably in the days of System 6), I had a utility that could format a completely blank disk. I don't know if a similar utility is available today.

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Answer 6

Long Lane

Level 1

105 points

Jun 1, 2019 8:35 AM in response to iTBotB

If the disk is not broken, it should show up with running 'diskutil list' in the terminal. Maybe it will have a different number to disk2, but it should be there.

From experience, Disk Utility can cause problems and I ultimately have to resolve to using the CLI.

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Answer 7

HWTech

Level 9

60,650 points

Jun 1, 2019 9:46 AM in response to iTBotB

macOS does not change disk IDs except after a reboot. If the drive is physically not seen by the system, then plugging in another external drive might populate the now empty "disk2" spot without needing a reboot, but it is not guaranteed. Also the disk IDs assigned various drives will vary depending on how each drive spins up so "disk0" is not guaranteed to be Bay1 each time if the system has multiple drives.

If Disk Utility did not finish erasing the drive, then you may have a failing drive. If this is not the boot drive, then you can check the health of the drive using DriveDX.

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Answer 8

iTBotB Author

Level 1

43 points

Jun 1, 2019 3:23 PM in response to Grant Bennet-Alder

You have an earlier version of Disk Utility. My version is crippled and does not have the View option.

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Answer 9

Jun 1, 2019 7:03 PM in response to iTBotB

View menu is in High Sierra and Mojave. Older versions show all disks by Hardware-name.

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Internal hard drive "gone"

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