Since a recent power-cut I've had problems writing (cloning with CarbonCopyCloner fails) to an almost-new (a few months) WD external disk...
I'd had similar issues with some of the other external disks used by two Macs here, but using DiskUtility to build replacement directories has sorted them.
The disk is used solely as a clone of another holding a/v files. I don't process any info on it, just clone with CarbonCopyCloner.
CCC has reported various errors - including 'physical problem' and 'damaged files on destination'.
After a directory swap with DiskUtility, it'll write what it previously failed with, but the issue repeats within hours.
As DiskUtility initially fixes it, I initially thought it may be a corrupt directory - but as the issue returns, maybe this isn't the issue.
I wonder whether the power-cut screwed something (but I don't know what) on my Mac, and that this then re-corrupts the directory on the external disk.
I don't know if it's relevant that the disk is almost (about 129gb free on 3tb) full - over the years I've never had issues with any other disks, all of which have had less (and sometimes just a few kb) free space.
Perhaps 'bad blocks' may be the issue... although my understanding is that when a bad block is encountered the disk will simply write elsewhere to a good block - so, assuming there's enough good blocks available, the write will complete (but slower).
For now, I have another copy of the info on that disk - and a replacement on which to store it.
If I knew the disk is genuinely damaged I'd not hesitate to discard it - especially as it's within warranty.
But I'm reluctant to write-off what might still be a good disk, and hence am about to reformat and see if the issue re-occurs.
Having ruled-out a surface scan (it'll likely take too long) I'm about to reformat the disk and then see how it behaves.
I'm considering a one-pass zero-wipe with DiskUtility, but have read conflicting info on the merits thereof... some say 'do it because DU will then map-out bad blocks so they're not use, whereas others say 'don't bother because normal writing will do that anyway'.
Suggestions appreciated - please and thanks.
UPDATE: Having made various efforts with DU to reliably erase the disk, after which it now fails to write when manually dragging files to it using the finder, I'm concluding that the disk is indeed faulty and shall return it for replacement.
I'd had similar issues with some of the other external disks used by two Macs here, but using DiskUtility to build replacement directories has sorted them.
The disk is used solely as a clone of another holding a/v files. I don't process any info on it, just clone with CarbonCopyCloner.
CCC has reported various errors - including 'physical problem' and 'damaged files on destination'.
After a directory swap with DiskUtility, it'll write what it previously failed with, but the issue repeats within hours.
As DiskUtility initially fixes it, I initially thought it may be a corrupt directory - but as the issue returns, maybe this isn't the issue.
I wonder whether the power-cut screwed something (but I don't know what) on my Mac, and that this then re-corrupts the directory on the external disk.
I don't know if it's relevant that the disk is almost (about 129gb free on 3tb) full - over the years I've never had issues with any other disks, all of which have had less (and sometimes just a few kb) free space.
Perhaps 'bad blocks' may be the issue... although my understanding is that when a bad block is encountered the disk will simply write elsewhere to a good block - so, assuming there's enough good blocks available, the write will complete (but slower).
For now, I have another copy of the info on that disk - and a replacement on which to store it.
If I knew the disk is genuinely damaged I'd not hesitate to discard it - especially as it's within warranty.
But I'm reluctant to write-off what might still be a good disk, and hence am about to reformat and see if the issue re-occurs.
Having ruled-out a surface scan (it'll likely take too long) I'm about to reformat the disk and then see how it behaves.
I'm considering a one-pass zero-wipe with DiskUtility, but have read conflicting info on the merits thereof... some say 'do it because DU will then map-out bad blocks so they're not use, whereas others say 'don't bother because normal writing will do that anyway'.
Suggestions appreciated - please and thanks.
UPDATE: Having made various efforts with DU to reliably erase the disk, after which it now fails to write when manually dragging files to it using the finder, I'm concluding that the disk is indeed faulty and shall return it for replacement.
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