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Bad sectors on hard disk

Last response: in Storage
February 6, 2013 9:19:09 AM

How to repair it please? Any free software available to automatically repair bad sectors of the disk?

More about : bad sectors hard disk

a c 359 G Storage
February 7, 2013 3:26:00 AM

You cannot repair bad sectors. The term "Bad Sectors" usually is used by Windows as it reports results of several utilities like SCNDSK. What it really means is that, during its testing, it found some Sectors could not be read reliably. So, it tried to copy the data there to another good sector and adjust the file allocation records to take this into account. Then it placed an entry in its own Bad Sector table that it keeps on the drive. From now on Windows will NEVER use that sector, or any others in that table. But you must be a little careful, because the copying of data from Bad to good sector MAY have copied BAD data because the source sector had a flaw. The big trouble is that these Windows utilities never tell you which files had the problem, so you can't know where the potentially corrupted file(s) is (are).

There are two ways to get rid of Bad Sectors, and neither of them is a repair. Each simply avoids ever using them again. And MOST IMPORTANT - BOTH of these completely destroys the data on the drive!!

The first is done using Windows itself - you Format the drive, doing a Full Format. As it does that, Windows tests all the sectors and replaces the old Bad Sector table with a new one. This does not eliminate those Bad Sectors - in fact, the ones that really are bad will be re-detected and put into the new table.

The second is to force the HDD itself to do the job and "hide" the results. This uses a normal background function of the HDD's own on-board controller. You need a utility that will "Zero Fill" the drive. This writes just zeroes to EVERY sector of the drive. In doing so it also tests every sector. If any are found to be questionable - even weak is found this way, not only really bad sectors - it is marked in the HDD's own hidden records and replaced with a known-good sector from a stock of spares. Actually, this process goes on all the time during normal operation, but sometimes it misses a few weak sectors. Anyway, when this is finished you have a completely blank drive like a new one, and it MUST be Initialized - that is, Create a Partition and Format that - so that Windows can use it. But at this point the drive does not let Windows see ANY bad sectors - they have all been replaced with good ones - so Windows will report no Bad Sectors.

To repeat, neither of these processes repairs Bad Sectors - there is no repair process. They each just replace bad sectors with good ones. And BOTH completely DESTROY all your old data on the drive.
a c 131 G Storage
February 7, 2013 3:45:05 AM

also before you you format your hard drive run hdtunes and read your hard drive smart report. drives do over time get one or two bad spots. the issue is if the hard drive heads heads are hitting the platter or if the media is going bad. the smart read will tell you how many sectors have gone bad and if there close to the drive vendor max count. if it is close you may want to see if your drive is under warranty and replace it. hard drive will start clicking or humming if the heads or bearings start to go.
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a c 100 G Storage
February 7, 2013 5:38:01 AM

Bad sectors:

1. COPY all data to another drive
2. Run a full diagnostic using the software from your hard drives manufacturer (should be a DESTRUCTIVE diagnostic which is why you copied your data).
3. Do a FULL FORMAT of the drive.

- if any data is already corrupted it can't be repaired
- the FULL FORMAT not only formats the drive, but also builds a BAD SECTOR table by writing and reading to every location; those areas that aren't reliable are blocked off. You should ALWAYS perform this prior to use the first time, especially before Installing Windows.
- both the diagnostic and format will take hours (perhaps 5 hours per TB)
August 5, 2013 3:48:05 AM

If you have bad sectors in your hard disk, running a program such as Microsoft CHKDSK or ScanDisk and performing excessive attempts to read the disk can make matters worse. Your best chance of successful recovery of your data is to take your drive to a data recovery specialist and allow them to examine the disk.

Read my data recovery blog for more information about sectors and the causes of bad sectors.

John Reid, Cheadle Data Recovery, Manchester, UK.