I moved some folders around on my system (from dropbox to google drive). This triggered a bunch of processing and eventually left my "System" taking 80+Gb's of space instead of 25-30Gb where it originally was. I have since deleted dropbox and google drive is synced up fine and only containing 13gb's. But System has been left in this state and now I have almost no storage space left!

  • Yes, My mac is meeting that problem, I have no idea why the storage report system is taking the huge storage. – Kevin Feb 21 '17 at 14:23

You can use ncdu to analyze your disk usage. From its homepage:

Ncdu is a disk usage analyzer with an ncurses interface. It is designed to find space hogs on a remote server where you don't have an entire graphical setup available, but it is a useful tool even on regular desktop systems. Ncdu aims to be fast, simple and easy to use, and should be able to run in any minimal POSIX-like environment with ncurses installed.

It is available on homebrew (brew install ncdu).


ncdu $HOME


ncdu /

You can install and see what is taking up your drive with:

  • Disk Inventory X
  • Grandperspective

Of course you can do it manually:

  • open Terminal
  • enter sudo su - and type your password when asked
  • cd / - start on root folder
  • du -d1 | sort -g - shows the biggest folder last
  • cd to the last listed directory (or one of the last to see what's in there)
  • repeat from du -d1 | sort -g and go as deep as you need
  • OK, I got this same answer on another forum which I why I had to ask again. These programs don't show system storage (as far as I can see). They will show me a detailed view of whats in Applications, Documents, Text Files etc.. All the stuff that is blue, purple, red and green in that image. The yellow stuff is not visualized by these inventory programs. This is a deeper problem. Those 80gb's were essentially generated overnight when I moved some folders around. – user5797668 Dec 9 '16 at 20:22
  • What about the manual method? this (as it is run by root) will for sure show the usage of the folders (and I deleted the -h option as sort on OSX sorts numbers only and not the M,G,..) – Zina Dec 9 '16 at 20:40
  • And unmount all network drives, disconnect USB drives. – Zina Dec 9 '16 at 20:43
  • are there any known issues with cloud filesystems like dropbox or google drive adding 80 hidden gigabytes?? – user5797668 Dec 9 '16 at 20:46
  • @user5797668 - No – Ramhound Dec 9 '16 at 20:46

You can install OmniDiskSweeper to browse and put to trash enormous files. I had a similar problem and it turned out to be old dev-related frameworks and simulators I didn't use anymore taking up to 50Gb, all placed under the "System" category in the Storage Manager. I guess you can achieve the same results without the soft I linked above, but it helped me locate and delete these files in a couple of minutes, so it's the best solution I found so far for an issue like this !


Also check the /cores directory - you can delete all the files here. Its only to debug which application is coring and why. You can always wait for it to happen again and go ahead and delete all the files here to reclaim disk space.

  • I'm not familiar with coring. Google does not give meaningful result. Are you sure it's not a typo? – Vylix Jul 14 '17 at 20:54
  • When an application ends abnormally, it can generate a core file stored under /cores. The size of these files are big and they build up over time. So, you can delete them to make space in System. – Megageek Jul 15 '17 at 23:31

If you have Time Machine active maybe you have pending snapshots to be backed up. Check it:

sudo du -hs /.MobileBackups

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