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My wife's Windows 7 (64-bit) box has suddenly developed a SMART "disk is bad" status. I'm attempting to copy everything off (no admonishments about lacking a backup regimen, please, I know already :( ) by creating a System Image across the network to a different machine, but it gets to a certain point and starts taking forever. Doing a chkdsk reveals that certain files cause this by having many bad blocks (like dozens of thousands in a row, if the event log is any indication) and causing the system to do its standard try-to-recover-and-relocate-upon-access thing.

But this is taking so long, I'm afraid the disk will fail completely before I can get the damned thing copied. However, several of the files so far have been ones that she has copies of elsewhere, so I am able to just delete them prior to retrying the backup to speed things up considerably.

So: is there some tool or procedure that will try reading each file, and upon hitting a bad block, just tell me about it and skip to the next file? So I can see which ones I can just dump and which I need to let it try to recover?

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4 Answers 4

When it comes to bad sectors on a disk, if there is no backup then what I do is get a backup image of it using a tool called Drive Snapshot:

  Drive Snapshot
  http://www.drivesnapshot.de/

When this tool encounters bad sectors, it keeps track of them in a separate text file (one bad sector per line, so you can simply count the number of lines in the file to determine the total number of bad sectors), which is also used as a cross-reference to find out which files used those sectors.

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+1, After this is done run Spinrite as suggested by happy_soil, it may repair bad sectors or recover data and move it to good sectors, when spinrite is done make another image using Drive Snapshot. –  Moab Feb 18 '11 at 16:31

run chkdsk /r in an elevated cmd prompt to locate bad clusters and recover readable info. This may improve your backup attempt reliability. Backup your files using simple copy afterwards. If this fails you can try data recovery methods that retry the read, however if chkdsk could not read the bad sector, you could repeat the chkdsk /r and try again. Multiple chkdsk /r and attempts to copy data is a good way to repeat attempts at bad sector data recovery. If chkdsk manages to read the bad sector once, it will write the data to a good block. Repeated chkdsk /r will continue to improve file integrity as long as the bad block can be read just once. If the data is gone, give up!

Once you have recovered data or given up and written it off, you could restore the drive to normal use again, but keep important data backed up somewhere else. It may be a good idea to copy all your data from the drive as much as possible then do a low level format followed by a repartitioning and slow/full format to allow bad sector re-allocation within Manufacturer system and NTFS bad sector list. Quick format won't mark bad sectors as bad.

chkdsk /b clears bad cluster list and rescans/updates bad cluster list. The bad cluster increase rate may remain stable and the NTFS bad cluster list should keep it under control, the drive may be safe to use again. Remember though that if all the hard drives factory allocated spare clusters have been mapped to bad clusters, then the drive can't map clusters in future and may be heading for eminent failure. Remember though that NTFS monitors bad clusters independently though, so this may not be the final end for the drive.

You may want to control and monitor future bad sector increments by periodically running chkdsk /b and monitoring for dangerous bad sector increment rates using sector scan software. If the drive shows signs that it's stable, it could continue working normally again for a long time.

If the drive continues to give you problems, drop it from a very high location, this will prevent you from wasting any more of your precious time on an obtuse hard drive.

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While SpinRite won't exactly do what you want, it will try to fix and recover data that are situated on bad sectors.

As per usual, your mileage may vary, but based from various user testimonials, it works as advertised. I use it personally to maintain my disks.

Check its documentation for further details.

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This would depend on your desire for the data based on your desire to do things without cost.

I recently reviewed CBL's new data recovery software and although this drive is technically still running, one of the features it had that I found worthy of mention was the ability to select the number of retry attempts for bad sectors.

In a case like this you can set it to 3 retries instead of the default, 20 or 30 I think. By adjusting this down to 3 you should still catch all data on weak portions of the drive without wasting crucial time on files that may already be beyond software recovery. Then when you've captured that round go back and select only the files that failed in the first attempt and retry a few times gradually increasing the number of retries to 10, 20, 50 until you get everything or the drive goes completely flat lined.

Alternatively after the first pass you could try spinrite as suggested by happy_soil to see if it can refresh the bad sectors but get the bulk of the data off quickly first as this level of failure is often caused by failing heads, pre-amps or cache in the drive circuitry. f this is the case and the faults aren't in the media, every second of ru time counts.

CBL's software is a bit pricier than similar competitors at about $100, but the only commercial one I've seen with that much granularity in the controls and decent support available if you need some help getting the settings worked out.

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