...and sometimes seems to achieve so little.
For example, an elderly PC (I mean, that's why we run this software, right? To keep old machines alive?) of an elderly relative (see attached screen capture) - the disk is less than 25% full, there are few and small fragmented files, and yet after maybe half an hour of working it hasn't defragged everything.
In my not so humble opinion when I start with 14 files of 62.6 MB in however many fragments, it should take only a few seconds to copy all of those files to somewhere else on the disk and then another even fewer seconds to copy them back in zero fragments, and done. No? Why not? Why ages spent grinding away, naming hundreds of files currently being worked on (too fast to read but I presume the same 14 files back and forth...? Or is it shifting the whole disk around to make the 14 fragmented files more comfortable?). And then at the end of it all it hasn't even defragged all the broken-up files.
One thing I am sure of is that it's a whole heap more efficient than the Windows' defragger. Sheesh that program hardly does anything worthwhile, and the last time I used it the effort it took to get it scheduled to run frequently was not worth the result.