Hi. I ran Disk Utility on an external USB 3 drive. First, by clicking on the device name "Toshiba Drive" it does its thing and the drive passes. However, when I click on the Volume - 3TB Logical Volume OS X Extended - First Aid fails - message is "First Aid process has failed. If possible back up the data on this volume". Also, an onscreen message, "You can still open or copy files on the disk, but you can't save changes. Backup and reformat as soon as you can". Question is why does it pass on device but not volume. What's the difference? I had just moved my media files from an older drive this one. For a day, it seemed fine. Should I reformat and then move all my media back to it again, or is this a bad drive? Not sure if this belongs here or in the Peripheral thread, if so, sorry about that. Thanks.