WD external disk error

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?

BC

Tried what exactly with windows?

my computer > E/F drive access?

yes that will get denied... should actually come up with a message about granting access unless its formatted with some other partition like reiser/etc

under windows you should be right clicking my computer and choosing manage then seeing the disk loaded...
Make sure you're looking at the right one... they load 2 disks... CD (WD Ware) + Open Storage
in the disk manager you'll see if it can read the partition format - if its ntfs / other - no matter what you'll be able to wipe the storage side via any OS but can't wipe the non-storage CD Side... not without a little firmware flash / using WDWare tools to turn it off

I'm wondering if he's seeing the virtual CDRom that these load... and not the actual storage...

Nara

@BC said:

Tried what exactly with windows?

Using diskpart to clean the drive

Ambarishrh

@BC I tried the Disk Management, Selected the 2TB WD HDD, it was not initialised. Tried to initialise the disk and got access denied error. I hope you read my initial posts, that I tried the same thing using Disk Utility on a MAC and dd command to clean the hard drive.

@nara Tried the diskpart as well but without success. I am actually checking Spinrite if that helps. Will let you know the results soon.