1) "Analyse" on the "File list" tab
2) Click the "Size" header-box twice.
3) Click the select-box in the headers to select all.
4) De-select the biggest 10 (or so) files.
5) "Defrag Checked" then "Analyse" again.
6) Maybe defrag some individual big files first if they have big bits near the top (highlight to show location).
7) Select all and "Defrag Checked"
8) Move to the "Drive C:" tab and "Defrag" to compact.
9) Compact a second time to tidy the bottom edge.
Reasons;
a) because defraggler takes files to fill a gap from anywhere, instead of as low as possible
moving smaller files out of the way first gets more big files unified.
So, developers, please change these "foibles", which are already in the "suggestions" thread.