I ran this HD utility called CrystalDiskInfo that displays some of the S.M.A.R.T. information on my drives. It is displaying a "Caution" warning on one of my drives because its "Reallocated Sectors Count" value is 263 (ideally it should be 0 as it is on all of the other drives I have tested).

I posted this question on another forum and the general consensus of the responders was to back up immediately and get rid of the drive. The drive is fairly new and only has 4575 hours on it. I just learned about this utility a few weeks ago, so I don't know when the reallocation of these sectors may have occurred, but it hasn't changed.

Can I trust this drive?

Update (9/27/2009): That reallocated sector count stayed at 293 until about a week ago when I noticed it went up by 1. Just yesterday, I noticed it's up to 659. It's under warranty and is going back to the manufacturer for replacement.

  • 3
    Thanks for pointing out CrystalDiskInfo! I like that they have a portable version. Commented Aug 20, 2009 at 23:47
  • You should never trust any hard drive. 100% of drives are guaranteed to fail eventually. "Further, 36% of drives failed without recording any S.M.A.R.T. error at all, except the temperature, meaning that S.M.A.R.T. data alone was of limited usefulness in anticipating failures." Always have redundancy of some type.
    – endolith
    Commented Jan 21, 2016 at 21:11

5 Answers 5


In my experience it's a toss-up. I've had one drive that had some reallocated sectors and a nasty whine that ended up outlasting some drives that gave no warnings before dying a miserable death. I actually chucked it because it was so noisy, rather than data loss.

However, for me, personally, at the first sign of problems in a drive, I backup then swap it off. Drives are cheap, online backups are cheap and if you're anything like me, your time is better spent elsewhere than trying to recover a drive.

  • I'll accept your answer based on your second paragraph. I don't think this question can be answered with a definitive "No!". But, as you said, drives are cheap so why take chances? Plus, this drive seems to be deteriorating (see my recent update to the question).
    – raven
    Commented Sep 27, 2009 at 17:32
  • Getting worse is never a good sign :)
    – emgee
    Commented Sep 27, 2009 at 20:49

Rather than just ditching the drive, you might want to just keep an eye on it first, to see if the reallocated sector count increases. If that count continues to increase, the drive is finding and mapping out more and more bad sectors.

I guess it depends on what this drive is doing - is it "mission-critical" or on a server? If so, I would be more nervous than if it's in a home PC not doing a whole lot (as long as you make regular backups of the data, which of course you should do anyways).

Edit: I just downloaded and ran CrystalDiskInfo on my harddrive here at work (an always-on PC, as we're a 24-hour operation), and it's logged 7739 power on hours and has 100 reallocated sectors.

For those who don't know, reallocated sectors are:

Count of reallocated sectors. When the hard drive finds a read/write/verification error, it marks this sector as "reallocated" and transfers data to a special reserved area (spare area). This process is also known as remapping, and "reallocated" sectors are called remaps. This is why, on modern hard disks, "bad blocks" cannot be found while testing the surface – all bad blocks are hidden in reallocated sectors. However, as the number of reallocated sectors increases, the read/write speed tends to decrease. The raw value normally represents a count of the number of bad sectors that have been found and remapped. Thus, the higher the attribute value, the more sectors the drive has had to reallocate.

Source: Wikipedia

  • I have tested other drives that have 18-35,000 hours and no reallocated sectors. In fact, this is the only drive with a value above 0 out of 9 drives that I have tested. That's what disturbs me.
    – raven
    Commented Aug 21, 2009 at 0:00

I have drive that has 165 of them for a long time now. They all happened at one time and never increased since (two years ago). I would just closely monitor that figure. If it is just one time increase, do not worry.


It depends on how critical the data on the drive is.

You should always keep good backups... but in your case, I would keep an eye on it. If the number of reallocated sectors is not increasing, it might not be a deteriorating problem. It might have been a manufacturing defect or a one-time bump.

If you want to squeeze some more life out of it, I would say "use it." Use it for static data (pictures, music, applications, etc) that you can recover from a backup if the drive fails. But I would tend to prefer my other drives for data that is a bit more important to you.


It might be a sign, but in general you should not be worried until the reallocation count goes to a high number.

Modern drives are so dense that reallocations are quite common.

On the Security Now podcast Steve Gibson has talked about this. See e.g. episode 196, near "there are sectors that are going bad before they have gone bad. ".

  • 6
    What is considered "a high number"?
    – MrWhite
    Commented Dec 1, 2015 at 17:10

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