My recent (2012) MacBook Pro failed suddenly and catastrophically last week with an "Invalid B-tree node size error" (a solid freeze and forced restart seems to have done it). After some forum perusing, I purchased and ran DiskWarrior on the drive with minimal success. It was able to create a new index that allowed me to save just a few of the files that had not been backed up. Most of the User directory contents were not restored by the DiskWarrior-created index, so I didn't save the changes that DiskWarrior had made. The non-backed-up files aren't worth paying for a full data recovery service, but if there's still hope that I could restore them with software, then I would be willing to pay the $150 that Apple is asking to return the drive to me after a full AppleCare replacement. So, that's the question. With a B-tree error, is there still hope if DiskWarrior has already failed?