My firewire enclosure has the Oxford chip. It rarely gives any problems. But the HD inside will not mount. It's not the enclosure causing the problem as it will mount other HD's. Disk Utility recognises the HD, but is unable to mount it. Disk First Aid gives the following message: Verifying volume disk4s10 Checking HFS Plus volume. Invalid node structure Invalid node structure Catalog file entry not found for extent The volume needs to be repaired. Error: The underlying task reported failure on exit 1 HFS volume checked Volume needs repair DiskWarrior was unable to help. TechToolPro cannot even see the HD. Anyone have any advice?