MacOS: can't understand what is using all my disk space

Solution 1:

Forget all of the other tools...use the command line!

sudo du -hd 1 /

will show you the folder sized from the root of your drive to a depth of one level.

• du is the disk usage statistics tool
  • -h give you a "human readable" output
  • -d 1 traverses a depth of one level. This is a good starting point to see where the culprit is
  • / is the root folder

You should run this with sudo to get an accurate count and avoid permission errors. When you find your "what the heck...", change the path to that folder and investigate. For example

• sudo du -hd 1 /what_the_heck_is_this_folder

and you'll start to get a clearer picture. Good luck.

Solution 2:

Have you checked your downloads folder? Clearing that out will free up space. Surprisingly I have seen people who never empty their trash folder which can often have GB's of stuff in there. Also open iPhoto and then click the iPhoto button then Clear iPhoto trash.

All of these should free up some space.

Solution 3:

My favourite tool for this is Disk Inventory X. It's got a fantastic graphical representation that I am struggling to describe using text. But basically it uses colour coded blocks - different colours for different types of data - and those blocks are sized according to how big the file or folder is. You can hover the mouse pointer over each block to find out the path/filename of the offending file. You can see instantly at a glance, what the biggest space hogs are. At least take a look at their web page so you can see what I mean about the user interface. It's free and I find it invaluable.

Download / read more here: http://www.derlien.com

Also, if you have an iPhone, iPod Touch or iPad, then check your iTunes sync settings - you will probably find that your iPhone (for example) gets backed up to your computer every time you sync it. I have an iPad Mini and an iPhone 5S - I see four subfolders under ~/Library/Application Support/MobileSync/Backup and they are about 15GB each.

To check for yourself, press Shift+Cmd+G while you're in Finder, and enter the folder name ~/Library/Application Support/MobileSync. Highlight the folder Backup then press Space to bring up the Quickview window (which will tell you the total size of the Backup folder).