WD external disk error

Ambarishrh

I have a 2TB WD external disk and when connected gives me an error "The disk you inserted was not readable by this computer". In disk utility, the disk shows up with partition map scheme as unformatted, and option for partitioning is greyed out. Checked using diskutil
sudo gpt recover /dev/disk2
gpt recover: unable to open device '/dev/disk2': Permission denied

sh-3.2# diskutil repairDisk /dev/disk2
Nonexistent, unknown, or damaged partition map scheme
If you are sure this disk contains a (damaged) APM, MBR, or GPT partition map,
you can hereby try to repair it enough to be recognized as a map; another
"diskutil repairDisk /dev/disk2" might then be necessary for further repairs
Proceed? (y/N) y
Error repairing map: Couldn't read partition map (-69876)

Is there any other tools I could use to check this?

Nara

Are you trying to recover info from it, or just wipe and use it?

BC

any of these simply need another power supply..
Unless its making clicking sounds, I usually try another ~same power supply. Have had both Seagate and WD do similar things.

Ambarishrh

@Nara I just want to wipe it and use it again.

Ambarishrh

@BC Its a small external hard drive, WD Elements without additional power, just the USB

jasonh

If you're not worried about losing any data on the drive and just want to wipe the GPT table so you can start over from scratch, run these two commands:

dd if=/dev/zero of=/dev/disk2 bs=512 count=2
dd if=/dev/zero of=/dev/disk2 bs=512 count=2 seek=$(($(blockdev --getsz /dev/disk2) - 2))

The first one wipes the GPT table from the beginning of the disk. The second one wipes the backup copy from the end of the disk. GPT keeps two copies, in case one gets corrupted, so you have to wipe both.

Ambarishrh

@jasonh Thanks!

I tried but didn't worked.

diskutil list

/dev/disk1

0: *2.2 TB disk1

dd if=/dev/zero of=/dev/disk1 bs=512 count=2
dd: /dev/disk1: Permission denied
Ambis-iMac:~ ambarishrh$ sudo dd if=/dev/zero of=/dev/disk1 bs=512 count=2
Password:
dd: /dev/disk1: Permission denied

scottalanmiller

Are you sure that you have sudo permissions?

Ambarishrh

Yes, I did run the command with sudo, and I am the admin for my MAC.

Ambarishrh

sh-3.2# dd if=/dev/zero of=/dev/disk1 bs=512 count=2
dd: /dev/disk1: Permission denied

Nara

Do you have access to a Windows machine? You could use diskpart and clean the drive to wipe it out.

Ambarishrh

@Nara I do have one. Let me check in that.

RoguePacket

OS X side, Disk Utility is used for this: repartitioning, formatting, et al. Gets grumpy with NTFS, but not much a hassle when wiping.

Katie

@RoguePacket said:

OS X side, Disk Utility is used for this: repartitioning, formatting, et al. Gets grumpy with NTFS, but not much a hassle when wiping.

I concur - if you're keeping it Mac side, NTFS is not the way to go.

RoguePacket

@nara @katie

Ah, that reminds me, OS X is read-only for NTFS. Should be fine to wipe with Disk Utility, but most other operations would fail (sudo or no).

Curious, have not tried this...could be worth a shot as a test—

http://www.cnet.com/news/how-to-manually-enable-ntfs-read-and-write-in-os-x/

Ambarishrh

@Nara Tried on Windows, same issue- Access Denied! May be its time to get rid of that, but can't believe that the HDD is visible on disk management on both windows & MAC but can't access that!

Dashrender

have you tried a utility like SpinRite yet?

Ambarishrh

@Dashrender Thanks. Haven't tried it yet. Let me check that as well.

Dashrender

@ambarishrh said:

@Dashrender Thanks. Haven't tried it yet. Let me check that as well.

Spinrite isn't free, but they do offer a money back guarantee.

Nara

@ambarishrh said:

@Nara Tried on Windows, same issue- Access Denied! May be its time to get rid of that, but can't believe that the HDD is visible on disk management on both windows & MAC but can't access that!

Access denied? Were you running the command prompt with elevated rights?