$BadClus:$Bad fragments

What is and how do we get rid of $BadClus:$Bad fragments.

Defraggler v1.16 & v1.17 quits when it starts processing this large portion of the hard drive. When I look at several blocks $BadClus:$Bad fragments are referenced and mixed with actual file names. An 80gb drive with only 9gb of data.

My issue with $badclus: started with a crash of drafraggler, and it will not go away.

How can I get rid of the massive section of the HDD that now shows up as $Badclus:?

I have read explanations as to why the badclusters appear, but I am unable to find out how to rid the drive of them.

chkdsk finds NO errors! but they remain in defraggler.