Windows only 
There is no shortage of disk space analyzers available for Windows, and there’s no doubt that we’ve covered our fair share of them. The truth is that these apps can be really useful when you’re in a pinch, and I think that’s why there are so many floating around. The most recent I heard about was RidNacs, and it left me very impressed.
The screenshot above shows the simple yet useful interface it presents you with, and for the 60,814 files I have on my test machine it took less than 18-seconds for it to finish the scan. That’s not too shabby. When you combine the awesome performance with these features it is a sure winner:
- Group files smaller than a specified size
- Integrates into the Explorer context menu
- Create a favorites list of locations to scan
- Scan networked drives
- Save results to CSV, TXT, HTML, or XML
- Choose from a few different styles for the percentage bar
Some of those features shine above the competition, such as scanning networked drives, because a majority of free disk space analyzers offer those features as a way to get you to upgrade to a paid version. The only thing this seems to be lacking is a portable version that can be used without having to install the program. Other than that I find it to be a rather complete app for its purpose.
Fun tidbit: “RidNacs” is actually “scandir” spelled backwards.
RidNacs Homepage (Windows only; Freeware)
via FreewareGenius
How does this stack up to TreeSize Free ([jam-software.com])? I’ve been an avid user of that tool for many years, mainly to find out where the free space of my drive is going. :p
Well, I like TreeSize Free because there is a portable version you can grab, but the big benefit with this app (in my opinion) is that you can scan networked drives… which is something you can’t do in TreeSize without paying for it. I’m hoping they will eventually come out with a portable option to this app.
I am a big fan of WinDirStat because it shows you what file types are taking up the most space and in the visual chart that it generates it shows you where the really large files are.