I am reporting this as a bug because of the difficulty I had in finding why my hard drive free space had deminished so severely.
I can't tell you how long and how lucky I was to find this but there were 4 or 5 .txt files in C:\Program Files\Defraggler that were several gigabytes in size. One was over 7 gigs. Others were 3 and 4, I finally uninstalled Defraggler to be safe and regained about 15 gigs of hard drive space.
I really tried to find in the help and support area what these files are for, didn't want to delete them without some effort.
I did find an area referring to a cache saving that allowed multiple drives to be analyzed with data saved. I unchecked that cache option but even though it said that data would be "lost" but take up less memory the amount of free memory stayed the same. I was afraid to just delete the individual files, uninstalling defraggler did remove them all. I may reinstall defragger to see if it still saves such large files even with the cache box unchecked.
There was no easy way to find this, the .txt file seems to be a log like record of a degrag operation, but very long indeed.
I will try to check back to see if there is a comment on this, thought support would want to know about it.
The real problem started when another defrag program would not do the job unless I had 15% free space. So I went through and deleted lots of old files and data on this very old laptop. I still had only 14% and then I stumbled on those large files in the defraggler area, I now have 46%.
Always somethng.
thanks, best, gwakeen