Incorrect owner flags for directoy hard link (id=xxxxxxxx)

While running Apple Disk Utility repair on my external USB drive (which I use primarily for Backup), I started getting hundreds and hundreds of warnings:

Incorrect owner flags for directoy hard link (id=xxxxxxxx)
(it should be 0x2 instead of 0x0)

where the id was a 8 digit number, like 19831030, that increased with each message. After running all night, it repair didn't seem any closer to finishing. So, I killed Disk Utility. I set the USB Drive as my startup drive (fortunately, it has OS X on it), and rebooted into safe mode (Cmd-S).

Then, I entered:
fsck_hfs -yprdf /dev/rdisk1s2

Fsck_hfs gave me similar messages, but seemed to be running faster. Indeed, it finished in about 47 minutes, with errors repaired. I ran it again, this time with no errors reported.

To finish and reboot, I entered:
shutdown -r now

After reboot, I switched the startup disk back to my built-in hard drive, and restarted. Once restarted, I ran Apple Disk Utility on the USB drive again. It found a minor error, and repaired it. Since then, it has been repairing fine.

I still have no idea why the USB drive started misbehaving. My guess is that one of the kids interrupted a backup by non-gracefully powering down the machine. Anyway, I hope this trick helps others.

Children: Agents of Chaos

I love kids. Especially toddlers. They are unpredictable and sometimes unstoppable. They haven't learned what things should and should not be pushed, thrown, leaned against, poured, stepped upon, eaten, flushed down the toilet, or inserted into the CD slot.