Disk Utility missing the Erase tab

Question

Disk Utility missing the Erase tab

Tonight, I was attempting to reformat my Mac Mini FileVault encrypted hard drive. I have Mountain Lion 10.8 installed on it, and I have a bootable Mountain Lion USB stick.

I booted from the USB device, and first tried to format. Everything was greyed out. I had to "Unlock" the encrypted drive and then it was available.

I then tried to do an Erase, and it failed with an error I didn't catch, and then only "Macintosh HD" shows up (no volume below it in Disk Utility) and the Erase tab is unavailable. The Partition tab is also locked and nothing can be chosen.

I can Verify and Repair with no problems, but I am unable to repartition or erase the drive.

Any thoughts?

Mac mini, OS X Mountain Lion

Posted on Aug 22, 2012 6:17 PM

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Answer 1

Shootist007

Level 6

16,703 points

Aug 22, 2012 6:20 PM in response to Allen Huffman

Boot into the OS and Remove/disable the File Vault.

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Answer 2

Aug 22, 2012 6:24 PM in response to Shootist007

The drive is clobbered. When I boot, I get my Login/Password screen immediately, like normal, then the spinner with a grey "NO" (circle/slash) and it just hangs there. The format that failed was enough to clobber the volume so it does not appear to Disk Utility.

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Answer 3

Shootist007

Level 6

16,703 points

Aug 22, 2012 6:33 PM in response to Allen Huffman

So even if you boot from the USB stick that has the ML install files and you use DU the drive does not appear?

If that is the case then the drive is FUBAR. The only option I know of in this situation it to use the manufacturers utility to Rewrite the drive back to factory specs. If that is even an option with these newer drives (haven't had to do that in some years).

But then you may need a Windows PC to do that.

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Answer 4

Aug 22, 2012 6:57 PM in response to Shootist007

The boot screen shows Macintosh HD and the USB device. The installer only shows the USB device, greyed out.

Disk Utility shows "Macintosh HD", but not the volume under it. (See screenshots.)

I went to a Terminal and did a "diskutil eraseDisk JHFS+ /dev/diskX", then it started showing up again in Disk Utility.

This may have me running again. I will post closing comments when Disk Utility is done 0-byte formatting the entire drive.

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Answer 5

Nov 24, 2012 11:39 AM in response to Allen Huffman

I ran in to this issue once again, when trying to clean install Mountain Lion on my MacBook. I rebooted to the Recovery partition, and tried to format/erase using Disk Utility and that failed and left the system where only the drive (Macintosh HD) would show up, and Erase was greyed out. I was unable to format using the command line due to seeing the message:

"The disk is in use by Core Storage as a Physical Volume"

I found a solution here:

http://apple.stackexchange.com/questions/59026/how-to-install-mountain-lion-on-a -disk-that-cannot-be-formatted-in-recovery-mode

See the post by Anderson, where he shows how to clobber this Core Storage volume:

Basically, you need to run
diskutil CoreStorage list
from Terminal. Identify the logical CoreStorage volume from that list and note the UUID string.

Then type
diskutil CoreStorage delete UUID
where UUID is the string you identified.

You can then partition with Disk Utility and run a Mountain Lion install.

This did the trick for me, and I was then able to 0-byte format the drive and do a clean install over the internet.

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Answer 6

Nov 29, 2012 9:02 AM in response to Allen Huffman

Thank you! This saved me. I was about to clean install Mountain Lion on my MacBook. I booted from DVD installer than deleted my internal HD. It stopped and after that I couldn't mount my internal HD. DiskUtiliy wouldn't mount it but in the same time reported that the HD was fine.

My FileVault password protection was on, btw. When I erased my internal HD, it asked for my password, after that it asked for a new password. I don't know if this is related.

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