I’ve got an m1 Mac Mini, which has 160 gig in systems data. It’s only a 256 ssd and I cannot update as there’s not enough space. I have deleted all Time Machine back ups, the cache, all browsers caches and even some apps, but I can’t get enough space to update. I know the Systems data should not be that big, but I can’t figure out how to reduce it. Can anyone help?
Rob
System Data taking up a large amount of storage is a common question on Mac.
There is no single setting that simply “clears” System Data because this category can include a variety of files, including caches, logs, temporary files, and APFS snapshots.
If you want the most comprehensive solution, back up first, erase the Mac, and reinstall macOS.
For Apple silicon Macs, use Erase All Content and Settings.
This removes your data, settings, and applications while leaving the currently installed version of macOS in place.
Make a current Time Machine backup before erasing anything. Apple: Back up your Mac with Time Machine
Afterward, use Migration Assistant to transfer your user account rather than the entire old system, and reinstall only the applications you actually need.
If you do not want to erase the Mac, first determine what is actually consuming the space. DaisyDisk can provide a clearer view of storage usage, and Apple documents how to view APFS snapshots in Disk Utility.
The following Apple Community discussions document additional approaches. Results can vary depending on what is responsible for the storage usage:
Also consider moving large personal files—particularly Photos, videos, music, and other files you control—to an external SSD.
This is often a more appropriate way to free internal storage than attempting to delete files that macOS manages as System Data.
System Data taking up a large amount of storage is a common question on Mac.
There is no single setting that simply “clears” System Data because this category can include a variety of files, including caches, logs, temporary files, and APFS snapshots.
If you want the most comprehensive solution, back up first, erase the Mac, and reinstall macOS.
For Apple silicon Macs, use Erase All Content and Settings.
This removes your data, settings, and applications while leaving the currently installed version of macOS in place.
Make a current Time Machine backup before erasing anything. Apple: Back up your Mac with Time Machine
Afterward, use Migration Assistant to transfer your user account rather than the entire old system, and reinstall only the applications you actually need.
If you do not want to erase the Mac, first determine what is actually consuming the space. DaisyDisk can provide a clearer view of storage usage, and Apple documents how to view APFS snapshots in Disk Utility.
The following Apple Community discussions document additional approaches. Results can vary depending on what is responsible for the storage usage:
Also consider moving large personal files—particularly Photos, videos, music, and other files you control—to an external SSD.
This is often a more appropriate way to free internal storage than attempting to delete files that macOS manages as System Data.
It will take a couple of days to delete files. All you can do is request their deletion. The operating system then deletes them on its own schedule. Until then, the space for those deleted files gets added to System Data.
But even so, you will likely need to use a 3rd party storage tool to locate where your storage is being used. The display in System Settings > General > Storage is not helpful.
Thanks for this. I’m worried that if I do erase and start again that the systems data will not change. Do you think there’s any chance of this?
No chance unless you Restore Everything form a Backup
The thing that I find crazy in all this is why does Apple allow their system to be this way? What's the point of having a computer where the vast majority of space is taken up by things that you can't delete or even really understand why they are there in the first place?
I bought an M4 Mac about a year ago; it too has a massive amount of space taken up by its systems data. 117 gig. What's the point?
I've been a Windows user most of my life; is this the norm with Apple?
Rob
System Data Taking Up Too Much Space on a Mac?
I think your frustration is understandable. Seeing 117 GB or even 160 GB listed as “System Data” on a Mac with a 256 GB SSD is ridiculous, especially when it stops you from installing a macOS update.
The problem is that System Data isn't one big file. It's a catch-all category that includes things like caches, application support files, local snapshots, logs, virtual memory and temporary update files. Some of this is necessary, but some can be safely cleared out.
Here are a few things I'd check before considering anything drastic.
1. Try starting in Safe Mode
On an M1 Mac mini:
This can clear certain temporary files, although it won't solve every cause of excessive System Data.
2. Check for local snapshots
Even if you've deleted your Time Machine backups, macOS may still have local snapshots taking up space.
Open Terminal (Applications → Utilities → Terminal) and run:
tmutil listlocalsnapshots /
If snapshots appear, they may be contributing to the problem. macOS usually manages these automatically, but sometimes it helps to investigate them further.
3. If you still can't update
An external drive and a bootable macOS installer may be worth considering, depending on how much free space remains. However, an external installer doesn't eliminate every internal storage requirement.
Apple also has an official guide with additional suggestions: Free up storage space on your Mac.
So, is this normal with Apple?
Not to this extent in every case, no. macOS does need space for temporary files, caches and system operations, and it can reclaim some of that space automatically. But Apple's biggest failing here is that System Data is poorly explained and difficult to manage. You're given a huge number without an easy way to see exactly what's behind it.
On a 256 GB SSD, that can become a serious problem. You shouldn't have to spend hours hunting through folders just to install an operating system update.
I'd avoid wiping the Mac or reinstalling macOS for now. The best next step is to find out what's actually using the space. If you share your macOS version and the output of those two Terminal commands, we can narrow it down and work out what can safely be removed.
2037kenrob wrote:
The thing that I find crazy in all this is why does Apple allow their system to be this way?
The biggest problem here is that Apple is calling this "System Data". It isn't "System Data" in any way. It's just a by-product of a Spotlight search.
What's the point of having a computer where the vast majority of space is taken up by things that you can't delete or even really understand why they are there in the first place?
It's not that there's any "point" to it. It's simply poor design. Apple doesn't "allow" this. Apple designed it this way, and let's be honest here - because of incompetence.
You probably can delete this data, but maybe you shouldn't. The entire concept, the user interface, everything, is simply poor design. This may be data that you really want and need. Spotlight doesn't know that.
The biggest problem is that you're out of storage. Regardless of how poorly designed and thought out the whole thing is, when you run out of storage, it really goes off the deep end. Other than a very low amount of free storage, which will be very difficult for you to actually see, you can't trust anything the system tells you about storage when you get this low.
I bought an M4 Mac about a year ago; it too has a massive amount of space taken up by its systems data. 117 gig. What's the point?
That's not massive. That's normal.
I've been a Windows user most of my life; is this the norm with Apple?
Yes.
I spoke to my local Apple Store, and they said to book it in and they will fix it for me. I said, 'Just tell me,' and they said, 'No, we have to do it.’ Man, they must queue a mile long of Mac's being "fixed".
Rob
Perhaps an over simplification that may or may not be well received
Would the same 160 Gb of what is categorized as System Data be as much of an issue if the SSD drive had a Capacity of say 500 GB or 1 TB ?
2037kenrob wrote:
... the vast majority of space is taken up by things that you can't delete or even really understand why they are there in the first place?
That's not really correct; you can delete the vast majority of things taking up space on your Mac. You cannot delete the System, nor Apple apps that come with the System, nor can you delete certain hidden files -- but all those things combined take up a fairly small amount of storage. The vast majority of your space is taken up with your data and files. What can be frustrating is that the Apple storage tool cannot categorize some files so they get lumped into "System Data." You can get insight into how every megabyte of your storage is being used by using a third party tool. There are some free ones, but the best ones, such as DaisyDisk and Storeograph, have a small purchase fee.
I bought an M4 Mac about a year ago; it too has a massive amount of space taken up by its systems data. 117 gig. What's the point?
Most of "System Data" consists of your files. It's not a helpful accounting tool when the Storage tool lumps too many things into that category. One of my Macs has about 30 GB in System Data; another has 52 GB; and another one has about 106 GB in System Data, similar to yours. For that one, I have 180 GB in Photos libraries and other folders containing images and photographs, and they all in my Pictures folder. Yet the Apple Storage tool says I have 38 GB in "Photos" (38 GB is the size of my Photos System Library), and the other 150 GB of photos appears to be book kept partially in "Documents" (which is not the same as the user Documents folder) and in "System Data." So the real objection is not the storage being taken by "System Data," it is that the Apple Mac Storage tool doesn't provide enough detailed information about where the storage is being used. But that is easy to discern with the third party tools I mention above (there are others; I gave two examples of ones that I use).
One thing those third party tools helped me discern is that I had large folders of downloaded maps for several Garmin devices that I use, including a couple of bicycle computers. Some of those maps were downloaded and installed on those devices, but the map files remained in several folders inside my user Library folder (inside Application Support). When I deleted those, I recovered several tens of GB of space that had been used and categorized into the "System Data" folder. If you have large amounts of storage being taken up in your Downloads folder or unemptied Trash, those might end up lumped into System Data. Sort all your folders by size inside your Library => Application Support folder in case some of those folders are large; then you can investigate why. Sometimes iOS update files and iOS backup files get lumped into System Data, although they shouldn't because they should be shown as the "iOS Files" category, but sometimes they are not.
Macs don't just create stuff out of thin air and put it on your internal drive. The user puts things there, but the Storage tool does an inadequate job of sorting and clarifying for the user where the largest amounts of space are being taken up. That's a valid criticism but easily addressed through use of third party storage audit tools.
steve626 wrote:
Macs don't just create stuff out of thin air and put it on your internal drive.
Alas, my Mac did just that today. 466 GB free at 10am. 9.6 GB free at 2pm. Why? The only explanation I can find is that I upgraded this machine (my test rig) to 27.0.1 the other day. I guess I should've waited. This computer has been my test rig for over two years. Still haven't found an OS stable enough to upgrade the production system.
But I was very pleased that Storeograph's Monitor feature worked in the wild. Of course I tested it, but those were always contrived tests. I was totally surprised when that Storeograph alert popped-up out of the blue. I knew I had a few hundred GB free on this machine. Not today I didn't.
Unfortunately, when the OS gets down to 9.6 GB free, it gets pretty unusable. Storeograph's Explore feature stalled, so I couldn't see where this 450 GB had gone. I even checked the handful of other places that display actual free storage and those were wrong. Whatever was going on had totally locked up the storage system. I thought maybe Storeograph had some major bug for a minute.
But I checked system analytics with EtreCheck and it clearly showed my free storage dropping down to zero. The Apple "dasd" process spiked to 100% CPU (100% of a single core) when the problem started. After restarting, all my missing storage miraculously returned. But "dasd" is still camped out at 100% several hours later. No clue what that's doing.
So when people describe these strange, impossible-sounding events happening on macOS 27, I'm much less inclined to doubt them anymore. This is just insane.
etresoft wrote:
But "dasd" is still camped out at 100% several hours later. No clue what that's doing.
So when people describe these strange, impossible-sounding events happening on macOS 27, I'm much less inclined to doubt them anymore. This is just insane.
Never mind! I found the problem. The fix was very simple. All I had to do was running the following command as root in Terminal:
kill -9 <PID for dasd>; rm -Rf /private/var/db/DuetActivityScheduler; rm -Rf /private/var/db/powerlog/Library/PerfPowerTelemetry/BackgroundProcessing; rm -Rf /private/var/db/DuetActivityScheduler;
Easy, peasy! Now why didn't I think of that earlier today?
<sigh>
Systems Data bloated
