"alignment error" in /var/log/kernel.log

WD External Drives External Drives for Mac
1

My My Book Essential 3TB reports an “alignment error” in my OSX 10.6.7 kernel.log.

Jun 1 20:04:44 macbookpoe kernel[0]: USBMSC Identifier (non-unique): 574341575A30323334313336 0x1058 0x1130 0x1012
Jun 1 20:05:02 macbookpoe kernel[0]: NTFS driver 3.4 [Flags: R/W].
Jun 1 20:05:02 macbookpoe kernel[0]: NTFS volume name My Book, version 3.1.
Jun 1 20:05:02 macbookpoe kernel[0]: NTFS-fs warning (device /dev/disk2s1, pid 24408): ntfs_system_inodes_get(): $LogFile is not clean. Will not be able to remount read-write. Mount in Windows.]: USBMSC Identifier (non-unique): 251201005042078D 0x4971 0xce21 0x0

I reformated it HFS+ (non journaled) so I could write to the drive. I specifically wanted journaling off to speed up a large initial backup to the drive. I also disabled Spotlight indexing on the drive for the same reason. Upon remounting the drive as HFS+, OSX reported a cryptic “alignment error”.

Jun 1 21:18:35 macbookpoe kernel[0]: USBMSC Identifier (non-unique): 251201005042078D 0x4971 0xce21 0x0
Jun 2 01:42:06 macbookpoe kernel[0]: USBMSC Identifier (non-unique): 57442D574341533832303635393331 0x1058 0x1100 0x165
Jun 2 09:21:54 macbookpoe kernel[0]: disk1s2: alignment error.
Jun 2 09:26:26 macbookpoe kernel[0]: disk1s2: alignment error.
Jun 2 09:26:30 macbookpoe kernel[0]: disk1: alignment error.
Jun 2 09:33:51 macbookpoe kernel[0]: disk1s2: alignment error.
Jun 2 09:44:46 macbookpoe kernel[0]: systemShutdown true

The previous problems were found in retrospect. The first time I noticed a problem was when Disk Utility wouldn’t enable journaling. Here are the kernel.log errors corresponding to the failed journaling:

Jun 2 09:49:41 macbookpoe kernel[0]: USBMSC Identifier (non-unique): 574341575A30323334313336 0x1058 0x1130 0x1014
Jun 2 09:49:59 macbookpoe kernel[0]: disk1s2: alignment error.
Jun 2 09:50:46 macbookpoe kernel[0]: decmpfs.c:1354:decmpfs_read_compressed: cluster_copy_upl_data err 14
Jun 2 09:50:46 macbookpoe kernel[0]: decmpfs.c:1377:decmpfs_read_compressed: err 14
Jun 2 10:08:18 macbookpoe kernel[0]: systemShutdown true

At Western Digital’s request, I mounted the drive on a Windows machine and quick-zeroed it. I remounted it on OSX, repartitioned it in Disk Utility per instructions on the web site, and reformatted it. This hasn’t fix anything.

Western Digital support referred me to the forums, but this seems to be a brand new issue. If nobody knows, I’ll return the drive to the store.

Thanks for reading.

2

Hello,

I’ll suggest you to take the unit back to the store and replace it for another one.

3

Thank you for the suggestion.

Western Digital e-mail support recommended to ignore the error, which implies it’s a known issue.  They wouldn’t explain why the error was harmless, so I couldn’t trust the device.

I’ve returned the drive for a refund, and I’ll wait for the store to carry a new model and/or batch of units before trying again.

4

Can you try to format the drive with the WD Quick formatter?  Make sure you backup your information first.

http://download.wdc.com/advformat/MacWDQuick_Formatter_v1.0.0.5.zip

5

The WD Quick Formatter isn’t necessary with new drives if one follows  How to install a WD Advanced Format Drive on a non-Windows Operating System.  The Advanced Format Hard Drive Download Utility documentation also states: “If you are attempting a clean install of an Advanced Format hard drive into a system running one of the Operating Systems listed above the installation process follows standard procedure.”  As I mentioned in my original message, I am running Mac OSX 10.6.7 (Snow Leopard).

I can’t try the WD Quick Format utility.  As I mentioned in my last message, I’ve already returned the drive.