After a power-cut this week, I'm having continuing problems with some partitions of some usb external disks (WD MyBook) on two Macs. DiskUtility and DiskWarrior have been useful in fixing some things, but I've still unresolved issues: DU is unable to unmount for repair; DW reports 'disk in use' and thus isn't able to build a new directory, or 'unable to replace directory' having built a new one. These issues are intermittent, and have recurred after fixes with DU and DW, and erasing the partition (but not the entire disk) with DU. I'm currently trying to find a way to fsck through terminal, but currently can't get beyond 'it's corrupted, needs repair'. The issues have become noticeable during Carbon Copy Cloner backups - where they either fail or complete with error advisories. I want to get to the situation of having disks that work reliably, and whilst I think that the issue is 'simply corrupt data that can be fixed by erasing', I'm concerned that the power-cut (and perhaps a preceding spike) have damaged the disks and thus they're likely to prematurely fail. I'm reluctant to reformat the entire disks because a) I don't have others onto which to load the contents; b) Even if I did, with up to 5gb, it'll take days to write. c) It'll not show if there's an underlying problem with the disk rather than simply the directory/etcetera. Suggestions appreciated. Please and thanks, etcetera.