You all know the saying that "Insanity is doing the same thing over and over while expecting different results." (Right, Jim?)
Well, maybe not.
While doing some cloning of one external to another, Drive Genius popped up a window and said my 15" MBP's hard drive was corrupted and needed repair (number of volumes/files were off). OK, I booted to one of the externals (Mountain Lion install) and ran Drive Genius twice getting a failed repair. Tried rebuild... failure. Then ran Disk Utility which also failed twice giving me the "You need to Erase and Format, blah, blah..."
My copy of Disk Warrior was too old for the OS so I decided to just make sure I had all the recent items from the past day or two up to date, then reformat the drive and copy back the data. The alternative was to order DW and wait til it arrived. UGH.
So I hooked up the 15" MBP to the new 17" MBP via Target Disk Mode and got ready to wipe, etc. Then I thought, oh, heck, why not try Disk Utility one more time? Insanity?
Well, I proceeded to watch the little bar and info window do their thing and noticed that they had gone farther than before...then, ta-daaa!
Disk Utility reported it had fixed the drive. I ran Verify just to be sure and yup, it was OK.
Sometimes it does pay to try again, and again, and again...