Used defraggler on a totally good drive, hardware ok, chkdsk ok, other test utilities saying ok.
Defraggler seemed to work fine.
Then tried to undelete a file that was put on and then deleted after using defraggler, so quite a normal thing to do in normal course of computer work.
Undelete program could not find any deleted files anymore on that drive, stopped searching after just hitting the find button, also totally unusual. Tried several times.
Used other tools to see if drive is fine, chkdsk said drive clean, another tool said "security descriptors wrong". Another undelete program said "Sector Count Invalid , Start Sector Invalid".
Tried fixing MBR, MFT, just not partition, as this could have caused loss of all data.
Backup of all data succeeded, but errors still to be found. Then, after backup, a little test was done, moving a directory (incl data) with the result that the directory name was moved, but all data in it was lost. Thank God a backup was in place.
Can this be a result of defragging \System Volume Information\catalog.wci?
What else should one not do with defraggler?