I have a 250GB SDD, and AboutThisMAC is showing 191GB available, but ALSO showing the SYSTEM taking up 159GB. I've scoured the forums and cannot find an answer to this strange occurrence.

I already rebuilt the Spotlight cache (add HDD to privacy, reboot, remove HDD from privacy, reboot)

I also check the TimeMachine, but since I haven't used it, it had no backups

Help?! (and thank you)

enter image description here

  • Update - System Report shows only 50GB free. Pullin' my hair out! – davesnothereman Jan 17 '18 at 1:15
  • Do all the colored and clear items add up to 250 GB? If so - then this could simply be that the "system" is everything minus the parts in purple and blue and nothing is amiss other than the concept of what should be in "System" – bmike Jan 17 '18 at 2:24

It seems illogical but it is really not. The important distinction to note is that the screenshot does not say "192.29 GB free", rather it says "192.29 GB available".

This is because the system part (shown as 159.77 GB) includes disk caches. Most of these disk caches are purgeable, meaning that they can be automatically freed up when space is needed.

So you have 191.29 GB available for you to use when you want - but while you're not using them, the system is using them to speed up operations using caching.

  • Thanks, this is a heavily debated topic. Coming from a "windows world" free space is free space - used space is used space. The way they display this makes it appear there are files to delete to free up space, but I understand your explanation! – davesnothereman Jan 19 '18 at 17:10
  • I'm not sure I follow your Windows analogy completely. On Windows you'll similarly have the operating system store all sorts of things on disk for temporary purposes. When you look at free space on a drive in Windows, the space used for these purposes are not included in the free space - but rather marked as used space. You have to open up Disk Cleanup to see how much of the used space that can be automatically removed. – jksoegaard Jan 20 '18 at 4:27

Figured out the issue in my case.


cd /

If you see a folder called 'cores',

type cd cores

If not, you can ignore the rest of this post.

type ls

If there's anything in here then it's probably the cause or a significant contributor to your issue..

type sudo chmod -R 777 ./

Enter your password

type rm -rf ./

And yeah this is relatively safe to do. The files are just core dumps (basically diagnostic logs that are generated when your computer crashes, as far as I know)

The storage tab in my TopLeftCorner->AboutThisMac instantly registered the 150GB that was just made available.

  • ~/Library/Logs also has some logs though. I am not saying they should be deleted. But my cores folder is empty too and surely my computer has crashed a few times. – anki Sep 28 '19 at 5:24
  • When I looked up what the folder contained I found discussions.apple.com/thread/7852353 and several similar sources. The general consensus seems to be that they are at least safe to delete. But you're right in that I do not know much about the conditions for which they are generated or the issues they help to solve - so you may want to check the size of the folder initially and decide whether you think they are worth deleting. – Christian Meyer Sep 30 '19 at 22:38
  • If you want the system to calculate the size of your folders for you, switch to list view in Finder (the 5 horizontal bar icon), right-click any file and click 'show view options', and finally, 'Calculate all sizes'. For me to took roughly an hour for Finder to determine that the size of this folder was roughly 100gb. – Christian Meyer Sep 30 '19 at 22:40

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