It's a disk usage tool that shows what's eating your drive in a very easy to read tree map. Great for clearing the clutter. I notice it no longer properly reports the size of my HDs..... but I'm not too upset... it hasn't been updated in years and I don't exactly think it was designed for Win10.
Did you try running it as administrator? Any disk usage analyzer can only count the files inside the folders it has access to. If you are normal user = only folders you have access will get counted, which is why some are missing.
Run Directory Report as an Administrator That way it can find hidden files It is faster than WinDirStat www dot file-utilities dot com
SpaceSniffer works pretty well. It's free and you don't have to install it, just runs as an executable. Doesn't look as pretty as other programs, but it's got a nice feature of highlighting files and folders that are currently being written to or changed. You can find it on FossHub.
Not sure what you mean by "create size report". Care to elaborate? Attached are some top level basic images. The file reporter allows you to create reports based on Oldest, Newest. Temp, Duplicates, File Types, Attributes, Owners, Sizes, Names, Dates, and Depths. The last image shows all the files on C:\ sorted by file size and percentage of space occupied.