Unreadable/Unmountable USB Drive

Question

Level 1

9 points

Unreadable/Unmountable USB Drive

I've got a had drive that was being used for Time Machine that will no longer mount. The drive is visible in DiskUtility but there is no partition and it is listed as "Read Only". All options to re-format, partition, repair, etc are greyed out. I've seen this before but I am not sure how to fix it.

The power went out during the first back up of the MacBookPro using Time Machine (long enough for the battery to die) and since then the partition is busted and the drive will not mount. It was formatted with GUID & Journal Extended.

Since there is nothing on it we care about is there any way to re-format the drive completely so we can start over?

Thanks,
Grant

MacBook Pro, Mac OS X (10.5.3)

Posted on Jun 26, 2010 1:04 PM

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Answer 1

Lyssa

Level 8

41,327 points

Jun 26, 2010 1:13 PM in response to renderbox

The only suggestion I have is to try reformatting the drive on a Windows machine and see if the Windows machine can do anything.

My suspicion is that the power outage damaged something within the drive, which is causing this strange behavior.

~Lyssa

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Answer 2

Jun 26, 2010 1:16 PM in response to renderbox

renderbox wrote:
is there any way to re-format the drive completely

In Disk Utility can you select that drive, select the "Partition" tab, and set the "Volume Scheme" to "1 Partition"? If so, then you should be able to reinitialize it.

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Answer 3

renderbox Author

Level 1

9 points

Jun 26, 2010 8:51 PM in response to William-Boyd-Jr

That's actually the problem. Right now when I try to do anything to it it says it can't read the disk.

What I think it odd is that it says "Locked - Yes, Writable - No" in the Drive information. It seems from what I can tell that it needs to somehow get unlocked before I can re-format it.

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Answer 4

renderbox Author

Level 1

9 points

Jun 26, 2010 9:09 PM in response to renderbox

Here is what I've got from Disk Info:

Partition Map Scheme : Unformatted
Disk Identifier : disk2
Media Name : WD Ext HDD 1021 Media
Media Type : Generic
Connection Bus : USB
Locked : Yes
Writable : No
Ejectable : Yes
Mac OS 9 Drivers Installed : No
Location : External
S.M.A.R.T. Status : Not Supported
Disk Number : 2
Partition Number : 0

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Answer 5

Andreas

Level 4

1,510 points

Jun 26, 2010 10:27 PM in response to renderbox

You need to be aware of what Western Digital say about their external drives. See my two posts in this thread, and in particular the link I give in the first one.

Andreas

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