System Storage Taking Up Way Too Much Space in macOS Sierra

*FIXED*

Hi! I have found a way to fix your problem! Some applications or folders in your MacBook library are more storage-consuming than they look. I had Steam Engine installed on my MacBook which surprisingly took 21 GB of my storage up. You can solve this problem by downloading the OmniDiskSweeper [Free Download Here] and [Tutorial Video Here]. Make sure you don't delete the important files in the library folder (or your MacBook won't run properly). If the application is used correctly, it should free up 40% of your disk.

I used the omni thing and found my huge systems folder was actulay down the path of library to mail to some huge cahed files. I unlinked my email and then deleted so i did not lose any mail (not sure if i needed to do that or not). Now i have much more storage and my emails are still there when i log into gmail directly

I had tried migrating my old Mac unsuccessfully several times. I deleted the users and tried again. Turns out when I went under users, that there were still 4 versions of the user there. I deleted them and it removed 200gb. I'd check with someone to see if this will cause you issues, but it was definitely my problem with the huge system size.

Had a few conversations with senior tech support ninja who fixed the issue.

Seemed to be something with the './cores' area of system files, which stores logs and data from system or program crashes, or terminated processes. Or something like that. Seems my computer was holding on to all of these core dumps for some reason. Still have no idea how that could take up so much space so quickly, but my guy identified it, stopped the processes and deleted the folder. Now my system files are around 16GB and I have 772GB free for ....something else.

Kudos to Jim Siebert....

I found a Onedrive temp folder of 130 Gb. It was here: SSD⁩ ▸ ⁨users ▸ ⁨me ▸ ⁨library ▸ ⁨Containers⁩ ▸ ⁨com.microsoft.OneDrive-mac⁩ ▸ ⁨Data⁩ ▸ ⁨Library⁩ ▸ ⁨Application Support⁩ ▸ ⁨OneDrive⁩⁩ ▸ ⁨tmp.
Deleting it freed up a lot of space, but onedrive immediately started filling it again.

Attention any photographers on this thread!

I have this issue quite often and a lot of the time my Lightroom catalogue will be listed under 'System'. To clear your catalogue or transfer it somewhere else, go to; About This Mac > Storage > Manage... > Documents > File Browser > Pictures > Lightroom.

I have the incorrectly reported system storage issue at least once a month and this usually fixes it for me. However, this time my Lightroom catalogue is only taking up 11GB and my Storage still reportedly takes up 142.99GB... I don't use iTunes and haven't backed up my phone to my Mac lately or anything like that so I'm super confused as what's going on this time.

I even went to the Genius Bar 5 days ago and had it checked out. Got diagnostics run which all came back positive. We checked and I had 130GB free and the system was only taking up around 40GB. I haven't really done anything since so I'm extremely curious how my System has tacked on another 100GB ;/

I had 114.6 GB of "System" storage, but my computer only had a 256GB SSD, which means that "System" already killed half my computer. Including other work files, the computer was basically full, and the annoying "System is almost full" message keeps popping out. But your trick did work, it cleared about 40 GB, real helpful, thanks!

I also have faced this issue. I had lots of google backup files which i couldnt find very easily. Then I went to Task bar>Go>Go to folder and searched

~/Library/Application Support/

You may delete all unwanted files. I could free up almost 60 GB !!

It wont ham you even if you delete the entire folders. you may loose some saved passwords and files. Mac will restore other settings to the factory settings. Do it at your own risk if you are going for a complete delete

Same here. I tried watching the TTA vid with David A. Cox but that got me nowhere and I tried to delete some files and got just barely anything done. I am wondering what is causing all this. I would go through Finder and look through the System Files folder although it is grayed out which means I have no access. Ughh, great.

Have you tried deleting items in the ~/Library/Caches directory. I had the same issue on my mac.

My mac has 500GB flash storage and i detected the same storage capacity problem.

I navigated to the caches folder and discovered the file size was quite big (around 330GB).

After deleting the contents from the cache folder i proceeded to restarting the mac. logged in and emptied the trash.

if you try emptying the recycle bin, the Finder app usually prompts you that "the files could not be deleted as it is in use"

BTW, I tried to use Clean My Mac X but I was only allowed to free up to 500 Megabytes of storage, practically doing nothing. I would use Daisy Disk but you have to pay for that too. I don't want to do the trials because I don't want to get in to that mess of forgetting about the trial ( which has happened to me many of times with other services ) and then having to pay for it, perhaps not working etc. This MacBook I have is from 2015 and it is running Mojave with no problem and runs apps smoothly without much latency so it appearing with this much system storage is crazy to me. So I guess it's not Human Error. And if it's not Human Error then it's Apple's fault. Now I don't want to rant about Apple and the many things that they do wrong but it just seems like it. To add on, they haven't explained why this happens. I even took the problem to a technician from Apple on a phone call and he just said to delete the cache files which did nothing! He suggested that I should delete some of the apps I don't use because there are files that are in the system storage directory. But, here is the catch ... I did that before already and that also did nothing! Maybe because I don't have much downloaded other than 1 game, Google Chrome and Spotify. I tried to disable some apps but that didn't change anything except the fact that it appears it was "removed". Well, I guess that is that and I don't have much to do unless some miracle happens.

I fixed mine (System storage eating 130GB) by deleting 2 ICloud Archive folders and an extra Desktop folder. I suspected something had happened when I'd clawed back files from iCloud six months ago after realizing I couldn't work offline. I thought I'd stopped the iCloud crap, but realized that files were still being saved to iCloud archive folders, though not being uploaded to iCloud. Then there was this weird extra desktop folder I found. I moved them to trash and my system storage went to less than 40GB with 106GB in the trash. Nearly pressed empty trash then - but be cautious.

It was harrowing, because it was confusing about which files were in my reg folders and which were in the iCloud folders I wanted to delete. It did not help that the folders in the trash bizarrely still showed up on the Finder window margin. I thought those folders were kept and nearly Emptied Trash - but those folders were actually in the trash. Be cautious and look for "trash" written inconspicuously on a grey bar in the finder window when you click on the left margin folders to view the files. I carefully moved files around into different folders then pressed empty trash. Currently the system storage reads 29GB. Success.

Deeper info: When I did Command I on the icloud a archives and extra desktop folders, they were nothing - nothing could explain the huge system storage load. But one or more of those folders was doing something on a system level that sucked my GB dry. I suspect it was that extra desktop folder that I think was generated while I took back my folders from cloud. I removed the archive icloud folders from trash to test what it did to system storage before I deleted them forever. Putting them on my desktop did nothing really to system storage. However the extra desktop folder couldn't be removed from trash to test it's GB burden ("do you want to replace the existing desktop?"). I said F it , put back the Archive icloud folders into trash and deleted the them all. Went from system storage using 130 GB to 29 GB in that instant.

(I'd dealt with Apple Support 3 times, BTW. I deleted timemachine snapshots, I turned off timemachine, I didsome otherstuff they told me to do which was PAINFUL and did so, so, so little. Still had 130GB system storage).

What fixed this was my intuition and anger: I figured it out. I hope this helps someone else.

I fixed this. My system storage was over 100GB. After running disk daisy as a system admin, I found that nearly 80GB were in the hidden Document Revisions folder - which I think is just old autosaved versions of garage band or other apps. After doing more research that told me not to just up and delete those folders, I downloaded Onyx (https://www.titanium-software.fr/en/release_onyx.html) and ran the maintenance, including selecting automatically saved versions of documents and I got almost all 80GB of space back. Onyx download was free. I literally just did this so hopefully my computer won't crash in a few days but all is well for the moment!

I have been researching this issue because i also have it, I have found the best solution to the problem which is to use OmniDiskSweeper, the app allows you to see what is taking up all of the space on your MacBook and allows you to delete it straight away. Here is the link to the website to download the app: https://www.omnigroup.com/more , i hope that all of you can fix the problem using my solution because it worked for me and is easy to operate.

There is also a video tutorial here for all of you. :) enjoy!

I had a hidden file in Application Support file taking up around 50Gb but was listed as System Storage . It was associated with another User profile on my MacBook that I deleted (maybe why the file was hidden even to the admin profile?). Helpful lil app called OmniDiskSweeper found it for me and I could delete it thereafter. Really reccomend it.