This morning I go to work, plugged in my MBP and up popped a message referring to my time machine disk which read: I went on and tried a repair in disk utility and got the same message. This is at least the fourth time I have received this message. Each time I reformatted the drive and started time machine again. Now at home, I have the exact same external hard drive connected to an iMac, and have never had this issue. The difference is, the computer never moves, so the drive is never unplugged. So my question is, do the rest of you have this issue? Is the issue because HFS+ is unstable with external drives? Should I assume it's an issue with this particular HDD and replace it? By the way, yes, I always unmount the disk before unplugging it. Of course, I have goofed once or twice. However after each goof, I run disk utility to make sure there was no damage. I know for a fact that last night I did properly unmount the drive.