Hi, I have recently been getting the attached error alot. I ended up re-formatting the external hard drive which I keep TM backups on, but after a few days I get the message again. What could be the problem? I was hoping that when I updated to 10.5.5, the issue would go away. To be more specific, the external hard drive is a 500GB Western Digital 3.5" drive inside a generic USB enclosure. It's formatted as HFS+ Journaled. Can someone help me? Thanks.