Mac hard disk bad blocks

I should have stated at the outset that I'm thinking of any disk drive that does have a functional bad block recovery and b sufficient spare blocks. I did, still do, half-suspect a tangling of some sort. Maybe a better way of phrasing my original question … defocusing from Disk Utility, considering the secureErase verb of diskutil:. The October post by Grant Bennet-Alder seems clear enough re: Nov 7, Actually, despite all the noise in this thread, Disk utility is able to remove bad blocks from the usable pool on a drive when it is used to erase the a drive and write all zero's.

Now, the point about "your hardware is failing" isn't necessarily wrong, but it isn't necessarily right either. If you have a situation where a drive has bad sectors, and it's not easy to replace it, using disk utility can help. I have resurrected many hard drives and iPods this way, and MOST of them continue working indefinitely. Dec 14, 7: Dec 15, 7: Go talk with the disk vendors. If they're interested in discussing this, and that's not a certainty.

Or acquire data from a large provider, as Google and CMU did with their technical papers on this topic; here are links to some of the papers. My comments above are from common practice within large and enterprise businesses. Dinking around with a comparatively cheap disk that's tossing visible errors is not an effective use of repair time, and risks reoccurrences.

Disks always toss errors. If the error is outside what the EDC can recover, you're rolling in backups.

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Can pattern overwrites be used to force revectoring, or to demonstrate flaws in the EDC? Rolling in a full disk backup can have similar effects. But my preference is to swap the disk. Preferably swapping for an equal or better grade of disk, as the cheap disks are usually cheap for a reason; shipped with fewer spare blocks, or with less reliable EDC, or other such. Disks are cheap.

The cost of the repairs and data loss are more expensive. Feb 4, 1: As well pointed your answers are, you are not answering the original question, and regarding consumer device hard drives your answers are missleading. Consumer device hard drives ONLY remap a bad sector on write. In other words YOU would throw away an otherwise fully functional drive. That might be reasonable in a big enterprise where it is cheaper to replace the drive and let the RAID system take care of it. However on an iMac or MacBook Pro an ordinary user can not replace the drive himself, so on top of the drive costs he has to pay the repair bill for a drive that likely STILL is in perfect shape, except for the one 'not yet' remaped bad block.

You simply miss the point that the drive can have still one million good reserve blocks, but will never remap the affected block in a particular email or particular song or particular calendar. This happens regardless how many free reserve blocks you have, as the bad block never gets reallocated, unless it is written to it. And your email program wont rewrite an email that is 4 years old for you How do you come to the strange idea that writing several times makes a difference? How do you come to the strange idea that the bytes you write make a difference?

Suppose block is bad. And the blocks ,, to ,, are reserve blocks. All subsequent writes will go to the same NEW block. So why do you ask if doing it several times will 'improve' this? After all the awnsers here you should have realized: And no: I would try to find a software that finds which file is affected, then try to read the bad block until you in fact have read it that works surprisngly often but may take any time from a few mins to hours Then write the whole data to a new file and delete the old one deleting will free the bad block and ar some later time something will be written there and cause a remap.

Writing zeros into the bad block basically only helps if you don't care that the affected file is corrupted afterwards. Feb 5, 5: Thank you for your feedback, Angelo Schneider. Your reply refers to rewriting files or reloading data, and to the error recovery sequences which involve sector writes, which can via by rewriting the file or rolling in a copy of the file or through normal operations, and not to erasing or reformatting the drive.

On rereading my replies, I did indicate that; that reloading and rewriting and RAID can resolves issues with bad blocks through rewriting. As you correctly indicate, that's how sectors are revectored. The original poster was specifically interested in using erasure and reformatting as a step for recovering from bad blocks, which isn't a step I view as being necessary or even useful, and — when folks are resorting to reformatting a drive for bad blocks — is usually an indication that the drive is long past replacement. As for why the OP is referring to a multi-pass operation, some folks use that as a scrubber or as a way to expose additional failing blocks.

In the absence of a disk diagnostic, overwrites are also sometimes used for disk qualifications, and to try to force a disk over into overt failure due to heating or other problems. Not my preference, given I've had disks that don't read back the same data that was written; one had a two-byte "slip" in what was written, about two thirds through the disk. Sometimes a RAID build or rebuild is used, too. Yes, I do replace drives.

Andrew Vit: Thanks for updating with your status. I always appreciate finding out how the story ends. If it makes you happy, then no doubt it was worth the trouble. But IMO the "write zeros" reformat was overkill.

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Out of curiousity, could you check your SMART values again and see if the sector was in fact remapped? Reallocation count changed from 0 to 1? Or whether it was "just a corrupted CRC", a possibility that chronos mentioned in an earlier comment? The easiest way to force the drive to do its own bad block remapping is to boot from an Ubuntu Live CD , then open a terminal and run this command: This is going to take a while: Testing with random pattern: Alternatively, if you have unix tools installed on a different startup disk, you can download and build e2fsprogs.

Then just unmount the disk you want to check and run badblocks on it. Alphaman Alphaman 51 1 1. From the documentation: Matthew Elvey Matthew Elvey 3 9. I don't believe that this does a per-block read and rewrite like badblocks -n, which is frequently necessary to get the disk firmware to actually spare out the block.

It's bit of an old question, but still valid. What worked for me is the following: If possible start up from a partition or drive other than your main one. Make sure it's not the Mac's Recovery option if you want to use a 3rd party application to identify the corrupt files Identify all the files on your harddive that are corrupted due to bad blocks.

Check Hard Drive Health of a Mac with Disk Utility

I happen to use Carbon Copy Cloner to create a mirror of my drive as a backup it gives you a list of corrupt files. There are probably other tools around that can do this. Locate these files on your drive, and delete them empty the trash as well! Open Disk Utility and erase empty disk space by writing '0's. Please mind, this can still take some time, especially if you have a lot of free space.

Gerbie Gerbie 31 2. Sadly, SpinRite would likely do more harm than good on an already-failing drive. GrahamPerrin for one, it doesn't make sense to attempt to recover your data and write it back to the same known defective media. But ignoring that, as soon as SpinRite encounters an unreadable block, it tries and retries repeatedly before continuing.

Suspect your Hard Disk is in need of Repair?

I've run SpinRite on a failing GB hard drive in the past, and it ran for more than a month without completing. In short: GRC Tech Support confirmed to me that recovery to something other than the disk from which recovery is attempted is not supported in the current version of SpinRite. Amongst the utilities that I have used on Macs, one is outstanding for unmistakable alerts such as this: Warning The operation you are about to perform may cause data loss.

For its unmistakable warnings, for pre-purchase satisfaction and more, this answer is my vote of confidence in: Graham Perrin Graham Perrin 5 18 Horrible, Horrible advise above. I mean WOW-horrible advise. Sign up or log in Sign up using Google. Sign up using Facebook.



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Super User works best with JavaScript enabled. Hence, one should repair bad sectors on Mac as soon as you realize. These sectors are formed due to 2 reasons, one due to physical damage and secondly due to logical errors. As you can guess, physical damage is caused by dust accumulation or damage caused to the rotating movement of the hard disk. These damages are permanent and cannot be repaired. On the other hand, bad sectors caused due to logical errors can be repaired. These are often a result of your computer turning OFF suddenly when data is being written or accessed.

Virus or malware attacks are also other reasons for logical bad sectors.

Reviving a Hard Drive for Use With Your Mac

This prevents your computer from getting stuck each time it comes across those sectors. It may not be a big deal if there are a few bad sectors on your drive but if there are a large number of them, it can be indication that your hard drive is failing. And if you need to recover data from failed Mac hard drives , use Remo Recover data recovery software. All your data and partitions can be recovered easily using this tool. It is possible to repair bad sectors using a built in repair tool on your Mac. To run this tool, follow the steps below. Your disk will be repaired and an explanation of what has been repaired will be reported.

SMART for HDDs/SSDs as Fast As Possible