Defraggler definitely has at least two problems and two bugs.
Prbl 1: the "moves same alrdy defragged files". Does not detect a large alrdy fully defragged "string" of files but starts "moving them just a little" (for another ten or more hours, again and again).
Typically when a large "area" fully alrdy defragged, from start of disk, but a "the bug" in the middle.
Prbl 2: GOes into "blip" mode,"blip" from watching HD LED , or using resource monitoring for HD access, CPU usage, Memory free. That is, spends some 5-20s "doing nothing" (no HD access, little CPU usage) inbetween "actual work".
Typ when defragging, or moving the "list of fragm files" or a specific "block"
BUG1: leaves blue blocks in empty space, but clicking them says "no files". However, it seems there actually is files there?
Defraggler internal data corrupted, systematically, a;ways same way.
Then BUG2, which together with above problems makes a REAL problem.
Defraggler somehow messes up the access to some files (handful on 4-5 tested 2TB HDs).
This leaves undefragged "red dots" in the middle of otherwise fully defragged areas.
Interestingly the bug is not the one (normal) file that is left undefragged, but often it's neighbors.
Note, these neighbors are also "normal movable files", and no bad sectors, have run HDDREG repeatedly.
(been there, done that, "locked bad sectors" HDDREGH fixes, spare sectors, etc as well as othrws locked files)
HOWEVER, when telling defraggler to move these NEIGHBOR files the graphic screen of blocks typically goes "haywire".
Typically "broad stripes" of "wrong info" all over the graph-block display.
Yypical overflow or over-run of data, messed up linked lists, etc?
Note, this only happens during the defrag or move process, after that "normal display" returns, with the other problems as before.
NET RESULT. If one of this "bad red dots" appear fairly early on the HD defragging it will also go into "move same files again and again" during repeated defrag-attempts. Never gets past that spot, except by moving the undefragged and its neighbors to another HD and a new defrag attempt.
VERY IRRITATING, as defraggler "never" gets to the rest or last files on the HD.
THat is, without moving all alrdy defragged files "just a little" for another 40 hours.
Whats worse, sometimes in "blip" mode. One little 4kB cluster every 10th second.