After one day with my External drive which stopped working, today, without doing anything, it's working again and I'm very glad.

But, when I checked the Disk I saw this

enter image description here

On assessment it says: Disk is OK, one bad sector

It's that something bad? How can I fix this?

  • -- Depends on the sector ;-) -- Keep an eye on this. IF it is problematic you will see those bad sectors increase rapidly the next few months. – Rinzwind Oct 1 '15 at 12:17

A single bad sector may be entirely harmless and the drive may happily run with it for years.

But especially if you had experienced an issue with that drive it can also be a first sign of a dying drive. As it is an external drive you presumably use for backups I would not take this lightly. You need to find out about the cause of this warning.

Please do run a thorough self test on that drive to read out its SMART data. They will give you valuable additional information. Here's how:

Things to be worried about are:

  • too many reallocated sectors indicate that the drive's firmware will no longer be able to reallocate and hide bad sectors to a reserved area of that drive.
  • growing numbers of bad sectors over time indicate that your drive has an issue and it will fail in the near future.

From what we can see there are not too many data on that drive. So it may be fairly new. You may be eligible for a warranty replacement but you will have to ask the vendor.

  • @Lurrdock Ouch - that indeed may be more serious than I thought. An answer to this question gives some suggestions. First of all I'd check cables (replace with another one). Unfortunately for a 5 TB drive ddrescue to recover data may not be a good option. In any case if you get your drive mounted you should backup your files (but there is quite a risk that the drive will ultimately fail by just using it).... Good luck! – Takkat Oct 1 '15 at 13:46

One bad sector is not a problem at all. Keep an eye on it, so check regularly.
When it starts increasing dramatically in a short time the disk may fail soon.
The system marks bad sectors as unusable - fixing bad sectors is impossible.
However you can continue to using your disk at the current status of health.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.