Use a program like WinDirStat or JDiskReport and see what they report.
Also, at any time did you have your dropbox linked to OSX machine?
Download JDiskReport, and run it on your hard drive's root directory (either "Macintosh HD" or "/" - I can't remember how JDiskReport shows it).
That will show you where all your storage has gone, in a nice interactive pie chart. (Click on a segment in the pie chart to open a new pie chart for that folder's contents.)
JDiskReport it’s not as good but it’s free so there’s that.
Edit: Space Radar is way better, use this instead.
It's a tiny little tool that scans your whole hard drive and then makes some graphs to show you what's taking up all of your space! I've got a few hundred gigs of steam games, a few hundred gigs of TV (mostly Castle and Lie to Me), and a few hundred gigs of movies all crammed onto this poor disk.
If you have a lot of videos taking up space, I recommend getting H.265/HEVC versions of them. The videos take up about a quarter of the space with no loss in quality! The only issue is that very few processors or graphics cards have hardware support for it yet, so converting videos to it will take a long time, and playing them back will require a lot of CPU power for the software decoding.
This program will scan your computer and tell you which files and folders are taking up the most space.
I'll save everyone some time though, it's probably the porn folder...
use jdiskreport to scan the drive and find whats taking up all the space. delete or back up what you will. you can also use winrar to compress old stuff you won't be accessing for a while, this will take time when using best compression but will save you a little extra room.
If you want a lightweight file analyzer that visualizes memory in a pi chart, etc, I would highly suggest jdiskreport. I've used it in the past to manage files when low on storage.
Other is just data it can't categorize. Might be email data or iPhone backup or something else. Use Jdisk report or something similar to find the big files and delete if you want.
Diskitude : Ultra rapide mais peu de fonctionnalités.
Ridnacs : Rapide et complet.
Jdiskreport : Superbe, plein d'options de reporting, mais en Java.
I don't know anything about OmniDiskSweeper, but I recently used JDiskReport to clean up my mac. But the problem is maybe that the files are created with a useraccount that the one that is running the app dosen't have permissions to see any information about those files, but the build in tool by apple has the permissions?
Although I like DIX, I prefer JDiskReport - easier to drill into directories with a Pie Chart interface.
(The downside is that it is Java based).
http://www.jgoodies.com/freeware/jdiskreport
EDIT: And it does take a long time to scan a lot of directories...
But there's more to it than that. They're specifically wanting to remove little preference files that are less than a megabyte big. If it was to free up space, I could suggest a few things such as installing JDiskReport, so they could see what's taking up the most space on their system, or making sure the maintenance scripts are properly running. If it's a matter of wanting to reinstall a program from scratch, because it was not functioning properly, I would suggest things such as checking the console for error messages, to better understand the problem. If it's a matter of intending to sell the computer, and not wanting to leave anything on it, I would suggest restoring the computer using the recovery partition. Etcetera.
DaisyDisk is a good app for hunting down where your data went:
https://itunes.apple.com/us/app/daisydisk/id411643860?mt=12
Or the less slick (and free) similar app is JDiskReport:
CCleaner like /u/dbe7 recommended to do the actual cleaning. I always leave the Font Registry Cache and Unneeded Languages unchecked though. If you have Java installed or don't mind installing it JDiskReport is great for discovering what is using the space and displays it in a piechart format.
This may not be what you're looking for, but I'd like to mention it anyway. I use a piece of software every once in a while called JDisk report - it gives me a nice circle chart of my largest files and directories. You can click the slices or the file tree to explore.
That is maybe because your winsxs folder contains junk files. Run this to clean that folder:
Dism.exe /online /Cleanup-Image /StartComponentCleanup
And then run CCleaner to remove temp files. Would also recommend that you use JDiskReport to find out where all you space has gone.
TreeSize for Windows or JDiskReport for OSX
They let you know where space is being used up on your hard drive.
There is a quite similar Java-based (so its cross platform, I used to use it on Windows and now use it on Linux since I've switched over) tool called JDiskReport that might be of interest.
Run something like JDiskReport or WinDirStat They will show you whats taking up the most space. Also run CCleaner to make sure you are clearing out cache, and temp files.
Also, if you have hibernation set and or restore points those can eat up space as well.
JDiskReport. We use it all the time for running manual scans. If you needed to automate it, you could probably do so from Scheduled Tasks with command line arguments. Reports can be customized and exported to CSV.
Most of what I do is from the command line on remote machines (my favorite, ncdu, was mentioned earlier), but if you're tunneling X/using NX Nomachine/sitting at the console, check out JDiskViewer.
It's a java GUI app that shows pie charts for the contents of directories. Click on a slice, and you see a pie chart for that directory. It also shows top largest/oldest/newest lists too. It's a cool free tool.
This may help duplicate file detector article.
I have used the Auslogics software and it works but in your case I would think a JDisk report might be more useful for you. JDisk.