Cannot repair or erase external hard drive

Question

Cannot repair or erase external hard drive

I recently purchased a Transcend 1TB harddrive and partitioned it in two. One of those partitions can no longer be mounted. I cannot repair the disk or erase it. I would be happy if I could completely erase the whole hard drive and start from scratch. Can anyone offer any suggestions? The output from diskutil verifyVolume is

Started file system verification on disk4 James_TM

Checking storage system

Checking volume

disk3s2: Scan for Volume Headers

disk3s2: Scan for Disk Labels

Logical Volume Group 02004E72-5803-4B70-9E9C-63F6A68AEAA0 on 1 device

disk3s2: Scan for Metadata Volume

Logical Volume Group has a 16 MB Metadata Volume with double redundancy

Start scanning metadata for a valid checkpoint

Load and verify Segment Headers

Load and verify Checkpoint Payload

Load and verify Transaction Segment

Incorporate 0 newer non-checkpoint transactions

Load and verify Virtual Address Table

Load and verify Segment Usage Table

Load and verify Metadata Superblock

Load and verify Logical Volumes B-Trees

Logical Volume Group contains 1 Logical Volume

Load and verify 606252CC-9C2B-4006-BFE4-494D5CA8E592

Load and verify B379F48C-BD07-4702-AE92-D4E36BC031E7

Load and verify Freespace Summary

Load and verify Block Accounting

Load and verify Live Virtual Addresses

Newest transaction commit checkpoint is valid

Load and verify Segment Cleaning

The volume 02004E72-5803-4B70-9E9C-63F6A68AEAA0 appears to be OK

Checking file system

Error: -69845: File system verify or repair failed

Underlying error: 8: POSIX reports: Exec format error

OS X Mavericks (10.9.2)

Posted on May 12, 2014 2:09 AM

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Answer 1

mhadjar

Level 2

191 points

May 12, 2014 10:59 AM in response to slabofguinness

Are you booting off one of the partitions? If not, you can always use Terminal.app and diskutil command.

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Answer 2

May 12, 2014 11:08 AM in response to mhadjar

No I'm not. The output pasted above is from diskutil. The hard drive is basically useless now since I can't mount it nor erase it.

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Answer 3

mhadjar

Level 2

191 points

May 12, 2014 11:10 AM in response to slabofguinness

Can you post diskutil list ?

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Answer 4

May 12, 2014 11:13 AM in response to mhadjar

]/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *64.0 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_CoreStorage 63.2 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

/dev/disk1

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *750.2 GB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_HFS Mac HD 749.8 GB disk1s2

/dev/disk2

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Mac SSD *62.8 GB disk2

/dev/disk3

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk3

1: EFI EFI 209.7 MB disk3s1

2: Apple_CoreStorage 667.0 GB disk3s2

3: Apple_Boot Boot OS X 134.2 MB disk3s3

4: Apple_CoreStorage 332.7 GB disk3s4

5: Apple_Boot Boot OS X 134.2 MB disk3s5

/dev/disk4

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Sonam_TM *332.4 GB disk4

/dev/disk5

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS James_TM *666.7 GB disk5

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Answer 5

May 12, 2014 11:14 AM in response to slabofguinness

disk5 is the problematic one, disk4 is the second partition

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Answer 6

mhadjar

Level 2

191 points

May 12, 2014 11:21 AM in response to slabofguinness

Disk 4 and Disk 5 are separate disks. They are not partitions of a single disk.

A partition would show as

disk1 as the main disk

disk1s1 partition 1

disk1s2 partition 2

If there's nothing important on disk5, then run this command

diskutil eraseDisk JHFS+ Untitiled disk5

https://developer.apple.com/library/mac/documentation/Darwin/Reference/Manpages/ man8/diskutil.8.html

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Answer 7

May 12, 2014 11:24 AM in response to mhadjar

Thanks I'll try that tomorrow when I'm back in my office. I'm confused about the partitions since both of those disks are on the same 1TB external hard drive. Could you tell me how to distinguish between the physical hard drive and "disks"? And what's a volume exactly? Thank you.

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Answer 8

mhadjar

Level 2

191 points

May 12, 2014 11:34 AM in response to slabofguinness

A physical hard disk should show up as disk1, disk2, disk3, etc..

A partition will show up as disk1s1 disk1s2 disk2s1 disk2s2 disk3s1 disk3s2, etc..

A volume is an entity with a label assigned to it, ie 'Macintosh HD'.

A volume is not a partition. A volume can be larger than the size of the physical disk. (eg. A volume can be 10TB but the physical disk is currently only 2TB. However, you can only utilize 2TB of that 10TB unless you add additional disks AKA thin provisioning)

However, for some reason, if you are 100% sure your external is a 1TB single drive, then I'm not sure why its appearing as two separate disks.

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