...Disk Utility cannot seem to complete the repair of :-Incorrect number of thread records, invalid leaf count, invalid volume free block count. S.M.A.R.T. Status is "Verified". I know, for what that's worth.
Also, in anticipation, which would be the better utility, DW or TTP to try to address these problems.
Your HD has a directory problem that's beyond DU to repair. The utility of (my) choice to apply in such situations would be DiskWarrior, which specializes in directory rebuilding and fixing. TechTool Pro can do this too, but personally I prefer the DW approach. While the directory may be beyond repair, you won't know for sure until you try DW or TTP.
The SMART status suggests that the drive mechanism is still OK, and the drive can be used even if it would need to be reformatted in case the directory can't be fixed.
