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  Resolved:What is Best Utility to Fix with Data Intact? - HDD Blocked Sectors 
 Date Written 
john albrich Aug 01, 2012, 07:21pm EDT Report Abuse
Anyone recommend the "best" utility to resolve this?
Please note the highighted info re:
You need a read/write surface scan to remap the sector. The best option should be a tool that knows about what should be read from that sector so that it has some option to apply the best fix to the missing data.

Frankly, I've never run into this situation before (outside the lab) and have no idea if recovering these 2 sectors is even possible now that I'm a mere consumer.

I had planned to backup this drive, however, I want to backup with as much intact data as I can. Clearly that won't happen unless I "unblock" these two "blocked" sectors and first store their CURRENT data in reallocated sectors using the recommended intelligent read/write surface scan methodology.

Evaluation of SMART data on this Western Digital HDD reveals:

BLOCKING ISSUE : your hard disk has 2 offline uncorrectable sectors. Those are sectors that an offline scanning found as unreadable. Offline scanning is a process that can be automatically started by the hard disk logic when a long enough idle period is detected or that can be forced by some tool. Those unreadable sectors are identified and the hard disk logic is waiting for a write command that will overwrite them to try to remap them to spare sectors (if available). According to the Reallocated Sector Count attribute, your hard disk seems to have available spare sectors. A simple disk surface scan won't be enough to force the remap operation. You need a read/write surface scan to remap the sector. The best option should be a tool that knows about what should be read from that sector so that it has some option to apply the best fix to the missing data.

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john albrich Aug 03, 2012, 12:26am EDT Report Abuse
>> Re: Resolved:What is Best Utility to Fix with Data Intact? - HDD Blocked Sectors
I marked this "Resolved" instead of "Solved" as I simply decided to say to hell with the user's OS. She didn't have backups, so I backed-up the user data and unique apps to the extent possible using MacriumReflectFreeEdition (MRFE) and manual file copying via Windows Explorer. It took longer than I had hoped, but her problem is solved.

Interesting results:
When I connected the drive to my computer using a USB2SATA adapter, MRFE made a backup of the entire HDD without any problem. However, when I connected the SAME drive directly to a SATA port, I could NOT backup the drive using MRFE as MRFE quickly reported CRC errors (after successfully backing up about the first 10GBs of the drive). MRFE instantly aborts on any CRC error and the backup is "failed". I then re-connected the drive back on the USB2SATA adapter and MRFE successfully again made a backup with no errors being reported. Similarly, when I tried copying a file that I determined was involved in the CRC error, the file could be copied when the drive was connected via the USB2SATA adapter, but could NOT be copied when connected directly to a SATA port.An odd situation to say the least.

Even though she now has a new reliable HDD, here's how I "fixed" the 'offline uncorrectable sectors' issue on the old HDD. I'll put the drive through some extended testing and report if it's a 'solid' fix or not, and maybe post an update if the drive reports on-going problems over the next few months.

To fix the 'offline uncorrectable sector' problem, and contrary to the wording of the SMART analyses, it wasn't enough to use a simple forced-write on the bad sectors. For example, I used HDspeed to write to every sector on the drive (note: that destroys the OS-level partitioning and of course any data on the drive). But, that didn't fix the problem.

So, I used HDDscan and used the 'surface tests' using the 'erase' option and selected the region of the suspected bad sectors. (note: an HDD security-erase program might provide the same results)

Interestingly, the logical block level 'erase' not only cleared up the 'offline uncorrectable sectors' problem, but it ALSO improved the read tests of subsequent HDspeed and HDtune. You may know that some drives when read tests such as those used in HDspeed and HDtune are used, often show intermittent downward glitches/spikes in the performance. For example, it may be 'reading' at 100MB/sec and suddenly dip down to 40MB/sec for just a short time, then return to 100MB/sec for awhile, then later 'glitch' again from time to time. Well, after running the HDDscan 'erase' on the 2 suspected 'uncorrectable sector' regions, ALL those glitches/downward performance 'spikes' disappeared COMPLETELY on that particular drive for the ENTIRE drive...not just the regions I 'zapped'. I have no explanation for that result.

Interesting note: the initial SMART analysis reported that even though the SMART data for every attribute were within acceptable values (e.g. "OK"), the actual fitness of the drive for reliable use was reported as 0%. Many people also consider even seeing one 'offline uncorrectable sector' issue, it's an indicator of a drive that will progressively and quickly deteriorate and cause data loss. I found it incredible that the initial SMART analysis indicated the drive SMART attributes were ALL "OK" and yet the drive itself was classified as 'unfit' for use. Regardless, I'm going to try to rehabilitate the drive.

john albrich Jul 11, 2013, 08:09am EDT Report Abuse
>> Re: Resolved:What is Best Utility to Fix with Data Intact? - HDD Blocked Sectors

I installed Windows XP on this HDD and ran it in a standalone system for awhile. Over time, system operation occasionally hiccuped...but it was highly intermittent and the symptoms differed. Sometimes attempting to open an application would report it failed to open and would close, and issued that report everytime from that point on, yet the application still opened and worked perfectly.

Other times, running certain applications would cause the OS to lock-up. After re-installing they worked fine. NO errors are reported in the Event Manager, however HD Tune "long" surface test started showing a few more "red" sectors and Speedfan online SMART analysis reported "Current Pending Errors Count" and "Uncorrectable Errors Count" returned. They always appear near the beginning of the surface scan which appears to be in the physical region where Windows is installed.

Using the same HDD Scan "surface test" clears up the sectors again. Reinstall the OS...more bad sectors eventually show up...and repeat. I don't know if there would be a point at which these errors will stop developing...assuming the drive didn't run out of re-allocation sectors. But, I'm not going to force the issue.

It would be nice if I could somehow designate the first user-accessible X MB's of the drive as simply "not there" so any OS wouldn't use that region of the drive, but for now the workaround is to not ever use this as an OS or critical data drive, and a partition is setup to encompass the entire "bad sectors" region of the drive. That partition will be filled with a file(s) marked as "read-only" and simply won't be used for anything. It will be interesting to see if bad sectors begin to show up in more regions of the drive but I believe they won't. The failures develop only in what seems to be a clearly defined region.



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