Helping a friend with her 17" A1297 MBP with OS X 10.11.6,El Capitan. Her 2 TB My Book external drive used to run Time Machine, and has about 300 GB free. It stopped backing up. I ran Disk Utility on it, and get many errors. I looked for, but didn't see a log. I read the ~/Library/Logs/DiskUtility.log is not in this release. I created 6 screenshots, attached. I know of, but don't have Disk Warrior. What are some good free or inexpensive options to repair the drive?