Defrag in Defraggler Posted February 4 On 18/01/2020 at 18:08, nukecad said: Defragmenting a disc and defragmenting files are (slightly) different things. Defraggler will do either, but doing both is a bit counter productive. Defragmenting a mechanical disk will try to fill up the disc clusters to get all files together in 'filled up' clusters. That means that to fill up empty space in those clusters some files have to be split (fragmented) - so much to fill a cluster and the rest in another cluster. Defragmenting files will keep the files together without splitting them up, but that means that not all clusters will be full to the top. It's a case of choosing which you want to do. If you are short of disc space then defrag the mechanical disc to free up disc space. If you want files to open slightly faster (you won't even notice) then defrag the files. With the larger drives fitted as standard these days defragging has become much less important that it used to be with small capacity drives. Thank you so much for that comprehensive reply. You have explained all I need to know.