Hard Disk Monitoring

I have a 3TB Western Digital external HD that is showing 100% Performance but only 5% Health. I've used chkdsk to move the bad sectors, and reformatted the drive, but I still get the same 5% Health reading that I did before. Self tests fail with the read element 0x79 message. Normally I would think it was ok to continue using the drive, but the test failure has me concerned. How risky is it for me to use the drive?

Thanks for your message.

I can confirm that chkdsk does NOT move bad sectors. Chkdsk never finds or repairs problems with the hard disk, but "repairs" problem only with the logical volume / partition. Even if sounds surprising, this may be independent form the actual hard disk status.

If there is a problematic sector found, chkdsk marks it to not use in the current partition - but it does not move, does not replace them from the spare area. This is not a solution as (for example) on a complete re-partition and re-format the sectors will used again and they may risk data loss.

In contrast, when a real hard disk test performed by using the surface tests in Hard Disk Sentinel, you can verify if the currently used data area is error-free, there are no further errors reported (no weak, damaged sectors, no further problems - or force the hard disk to really re-allocate sectors if required: to replace the problematic sectors from a spare area. Then the original bad sectors will be never re-used again, so they will not risk data.

The question is: did your hard disk re-allocate (really moved) all sectors to the spare area? Or is there any other sector(s) which can be damaged?
As the reported bad sectors may be high (if the health is so low) there is high chance that new and new problems may be detected from time to time.

For more information about these "bad sectors", please click on the "?" next to the text description
(the text area describing the issues) and check
http://www.hdsentinel.com/faq.php#health

For more information about the tests should be used to perform complete verification of the hard disk, to reveal and fix possible problems, please check:
http://www.hdsentinel.com/faq.php#tests

And to check how to repair the hard disk (and how chkdsk can't be used for this purpose):
http://www.hdsentinel.com/faq_repair_ha ... _drive.php

Alone from the health % (without knowing the complete status and the test results) it is hard to say anything for sure.
But if Disk -> Surface test -> Read test will show no errors (Disk -> Short self test / Extended self test will likely fail on a such low health), then you may continue using the drive - but only with constant monitoring and immediate backup on (even minor) change in health.
If you can use Report menu -> Send test report to developer option, it is possible to check the actual situation and advise.