I have recently changed my harddrive and Disk Utility already gives me this message that I have 8 bad sectors and that it is sign of imminent disc failure. It counts 8 bad sectors and I really dont know what has caused it. I have 4 partitions on it that work perfectly and I do use this harddisk to copy and move loads of data (music, movies, photos).

Can anyone tell me how I could fix it or prevent the disc failure?

By the way, these bad sectors are shown as a problem in the "reallocated sector count" section.


A small number of bad sectors is normal for any hard drive and are likely to be detected once you start using the drive. The time to be concerned is if the number of bad sectors increases which could be the result of a manufacturing defect and imminent total failure. For the small number of bad sectors that occur on drives normally the controller in the drive will automatically remap those to free space held in reserve for exactly this purpose.

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  • thanks for your answer. Does the remapping mean that the HD will correct these sectors on its own? I mean now it shows 8, is it possible that after this correction....it will show 0? By the way, way too much data on the HD can cause bad sectors too? – Elysium Aug 7 '12 at 17:12
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    The HD does the remapping on its own and will always report the 8 sectors that are bad that it has remapped. Storing data on the drive doesn't have any effect on whether there are bad sectors, bad sectors are not caused by having data on the drive. – mtinberg Aug 7 '12 at 17:19
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    Bad sectors are unusable. What the system does is say "Don't use this, put stuff here instead" in the free space that's kept for that purpose. Those bad sectors are then identified and generally avoided on the drive. Bad sectors crop up during a drive's lifetime, and is typically a sign of overuse. 8 bad sectors is nothing. Try 50000 on a drive I had that was near death. – Thomas Ward Aug 7 '12 at 17:20
  • @LordofTime ok, understood and accepted. :) Thx. – Elysium Aug 7 '12 at 17:24

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