Replace Drive in MyBookEssential 3TB - can not format on Mac

Hi. I needed to put the 3TB drive from my MyBookEssential in a raid enclosure and wanted to use the 1TB WD Caviar Green I swapped out as a replacement in the MyBookEssential case. I can now not format the drive in Disk Utility (“Unable to write to last block of device” error) I have tried to use both the “Erase” and “Partition” function with the partition map set to GUID or Apple partition Map -  no luck either way. If I try a secure erase it fails saying “Erase failed with error:” no other information. The drive does show up as 1TB capacity and I could format the drive without problems in a different external USB enclosure so I know the HD is fine. I have seen someone suggest that I should secure erase the drive first which I have done, still same results when putting it back inthe WD enclosure. I have updated the WD firmware and have installed the TURBO drivers from the WD site. I tried to use WD Quick Formatter but when I get to where it should show the drive I need to format the dropdown menu just has “item 1, Item 2, Item 3”. The Format Drive button is grayed out and stays that way no matter which “item” I select from the dropdown.

Pic.pngI am at the verge of just chucking the WD enclosure alltogether as I have now spent hours dong this without getting anywhere . . . Any suggestions would be appreciated. Thanks : )

I’m not a Mac user, but WD’s 3TB PC external HDDs are configured with 4KB LBAs, as reported by the USB-SATA bridge firmware inside the enclosure. WD does it this way in order to circumvent the 2TiB MBR limitation that would be present if the LBA size were 512 bytes.

Assuming WD’s external Mac drives are similarly configured, then you will need to partition and format your 1TB drive within the enclosure. If you partition it in a 512-byte LBA environment, such as inside a PC or in a third party USB enclosure, then the partition will look 8 times larger than it really is if you subsequently install the HDD, without modification, inside the My Book. In an NTFS file system, the last block of the partition stores a copy of the boot sector, so that may explain the “Unable to write to last block of device” error.

An additional complication is that SmartWare grabs about 700MB of disc space from the tail end of the user area for its VCD. Obviously your 1TB drive would have no SmartWare VCD, so I’m wondering how this affects the bridge firmware, if at all.

Yes, I appreciate that it would ideally need to be formatted inside he enclosure to work properly but I can not get any application I have to actually do it . . . .  any suggestions?

Sorry, I’m not a Mac user …

PROBLEM SOLVED !!! I have tried again, this time with the WD Smartware setup application. I realised it also has an option to erase the drive and it formatted the drive without any problems : ) Interestingly WD Quick Format still does not see the mounted drive (only gives the “Item 1” list in the dropdown menu) but Disk Utility can now also format the drive once it has been formatted with WD Smartware. Must be some proprietary WD thing . . .  They could really just make life simple and state “You will ONLY be able to format a new drive in the MyBook enclosure with WD Smartware” There are dozens of post online with people telling other people to throw their (presumably perfectly good) hard drives out because of this error . . . 

Hope this will help others as well : ))