Thanks for your message and sorry for the possible confusion.
This is possible and can even happen - if you are lucky.
In this forum and on the
www.hdsentinel.com (plus in the Help) such situation already described, discussed.
Hard Disk Sentinel (not Sentinal) does exactly what it should: detect and reveal possible problems/degradations which may otherwise remain unnoticed until they can lead to data corruption / data loss.
Yes, other programs may show failing drives as perfect: they do not care about the real number of problems. Instead, they simply check if the error level threshold reached or not. But this does not give information about the real problems, possible changes/degradations - which may be even more important than the current status and health %.
(if you are interested in further details, I'd recommend to check
www.hdsentinel.com/smart page).
As you can see, the count of bad sector is not zero, these are reported by Hard Disk Sentinel. You can verify on the S.M.A.R.T. page if you select the appopriate attribute(s) indicating reallocated sectors or uncorrectable sectors.
These "bad sectors" detected by the hard disk S.M.A.R.T. and thus reported in the text description are no longer used by the hard disk: they are already reallocated.
It means that a spare area is used for all reads and writes targeting those bad sectors, instead of the original sectors. This spare area is originally reserved, so the bad sectors (and the health decrease in general) does not affect the usable capacity.
This means that disk surface tests (even the surface test in Hard Disk Sentinel) will not access those sectors, but tests the remaining data area and the spare area. This is good, as this way you can be sure that the original (bad) area does not contain important data and can't risk data loss.
So ideally if all such sectors reallocated, the tests shows no problems. This is the IDEAL, best possible situation: in most cases, some sectors show retries and/or harder, slower accessible areas (these are yellow and darker green spots of the disk surface map in Hard Disk Sentinel surface test).
This is why the detected and reported bad sectors can never cause problems, regardless of their position because that problematic area is never used any more. Manufacturers prepared for this and even if it sounds weird, hard disks "allowed" to have more or less bad sectors and this is why other tools may never show / report them.
But without detection and reporting the amount of such issues, users may never know that the hard disk is not perfect and/or if there are new problems and degradation - until failure or "just" data corruption / data loss.
It is excellent idea to perform tests: to reveal possible further problems - or confirm if the disk status is now stable, all possible bad sectors already reallocated and the disk can be generally used without issues, without retries, performance loss and so.
This is why I also recommend testing in all such/similar situations - but with the proper tool which found and displayed the issues.
And if the hard disk is stable, the test shows no errors, yes, it is possible to acknowledge those problems (as they are already fixed) by clearing the error counter. So then Hard Disk Sentinel will show only possible new problems (if here will be).
Just the test types you used are far from perfect. If you check
www.hdsentinel.com site in general (for example the links below) you'll see that I do not write using _different_ tools as they may be simply not as effective, not as sensitive for problems as you'd expect - so (plus as their functions regarding status detection, error detection / revealing and repairing and regenerating all included in Hard Disk Sentinel) I see no point in using them for such purpose.
Chkdsk is one of the worst solutions if we speak about "bad sectors".
Even if this may sounds surprising, chkdsk does not check/verify/repair the hard disk itself, but verifies (and repairs) the logical drive, the partition only. The problems found and "fixed" by chkdsk are in most cases different than the actual hard disk problems: Chkdsk may find, report and "fix" problems on a perfect hard disk - and may not find anything on an almost bad hard disk.
(If you are interested,
https://www.hdsentinel.com/hard_disk_ca ... ectors.php page shows a such situation, illustrates how chkdsk can't really "fix" bad sectors).
So the question is: did the hard disk found all bad sectors and fixed them by re-allocating?
Or are there any further problems with the drive (for example weak sectors, spin retry issues, slower/hardly accessible sectors etc.) which may cause problems?
By the tests in Hard Disk Sentinel, you can verify if the complete disk surface area is error-free, there are no further errors reported (no weak, damaged sectors, no further problems, no retries or slower accessible sectors which may likely fail with normal use). Other tests may be simply not sensitive enough for all issues, do not report possible retries, slower areas, do not monitor operation conditions (performance, temperature) during the test.
And yes, if the tests in Hard Disk Sentinel show no problems, then you can be sure that the hard disk drive is stable and can be used (especially as its health shows GOOD) - even if the health shows less than 100%.
Personally I'd worry a bit - as based on the graph, the health descreased recently, so there may be further issue detected / reported.
So I'd use only with constant monitoring and backup of important data on any (even minor) new issue, health decrease.
If you click on the "?" next to text description, it clearly describes the situation about "Bad sectors".
Please also check the proper sections of the Frequently Asked Questions page:
https://www.hdsentinel.com/faq.php#health
https://www.hdsentinel.com/faq.php#tests
These describe the recommended steps to analyse the hard disks, reveal and fix any possible issues because the most important is to verify if the drive is stable (there are no more, currently hidden problems) - or confirm that the drive is now stable, all such issues already fixed by the hard disk.
And if these tests show no errors (which means the hard disk is now stable, all possible bad sectors are already re-allocated and fixed this way), it is possible to acknowledge the reported problems and remove them from the text description, to improve the health back to even 100% as then Hard Disk Sentinel will only report future issues (if there will be).
This is described at
http://www.hdsentinel.com/faq_repair_ha ... _drive.php
If you prefer, you can use Report -> Send test report to developer option any time (now and/or for example if you see new problems, decreased health), so I can check the actual situation and difference and may advise step-by-step how to diagnose and improve the situation.
