This is a frightening notification that some iPhone users have experienced. This happened to me while taking family photos on my recent vacation. It wasn’t the first time, but it was definitely an uncomfortable time.
Like most people who get a full hint of storage, I immediately went into Settings, then General, then iPhone Storage Options to see what was taking up that 256GB of space. Sure, I take a lot of photos and have dozens of apps on my phone that I no longer use that can take up much-needed storage space. I was hoping that if I could figure out what was taking up so much space, I could delete it and clear up some storage.,
But no one. This time my iPhone was not filling up with photos, apps, files or documents. This was “System Data”. A full eighty gigabytes of my iPhone, roughly one-third of its entire 256GB of storage, was being taken up by “system data.”

System data on the author’s iPhone grew to 80GB on Thanksgiving.
Credit: Mashable Screenshots
When I looked online, I found posts and threads on social media where other iPhone users shared their system data storage issues. One Reddit user’s system data was taking up 128GB of his 256GB iPhone!
And the worst part is that we can’t do anything about it.
What is system data?
When clicking on System Data, the very last thing on the iPhone Storage Settings page where all your apps and their file sizes are listed, iOS provides a very general explanation of what system data is.
It reads, “System data includes caches, logs, and other resources currently in use by the system.” “This value will fluctuate according to the needs of the system.”
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Here’s how the iPhone describes “system data”.
Credit: Mashable Screenshots
To be clear, this is not drive space that the operating system needs. It is completely free listed under iPhone Storage. The same is true with the data associated with each individual app. It is rolled out to the size of each app. This is something more vague. I contacted Apple for more information.
“System data includes caches, logs, and other resources currently in use by the system,” Apple said. “This also includes temporary files that have a short lifecycle and are being actively used by iOS to keep the iPhone running smoothly.”
You will find that system data fluctuates wildly. That 80GB of system data on my iPhone I mentioned earlier? Next morning it was down to 50GB.
“The size of system data is managed by the system,” Apple said. “When temporary files are no longer needed, the system automatically clears them, so changes in the size of system data are to be expected.”
How can users clear iPhone’s system data?
According to Apple, system data is basically what iOS decides it needs to store related to the apps and other processes that are currently running or in use. But, what if a user wants to quickly delete those temporary files to open up space. Can the user do anything?
Apple said, “iOS is designed to monitor and optimize storage usage, deleting as many temporary files and caches as possible to free up space as needed without any required action from the user.” “This automatic management takes into account the amount of available storage and helps ensure that iPhone maintains optimal performance while conserving storage space. Users don’t need to do this manually.”
So, in short, no. There’s nothing iPhone users can do manually to clear unnecessary system data when they need storage space. iOS decides what and when to clear. A Redditor on the Reddit thread mentioned earlier also shared how his iPhone’s 167GB system data suddenly dropped to 4GB on its own.
However, based on what Apple says and my own experience, this is what I recommend:
As soon as you notice that your system data is getting out of control, completely close all your unused apps. To do this, simply swipe up starting from the bottom of the screen. All your open app windows should appear stacked one behind the other. Swipe those windows up to close the app completely. System data will not be cleared immediately. Again, Apple says users can’t control this. However, closing those apps seems to move the process forward as those temporary files are no longer needed once the apps are closed.
Hopefully, one day, Apple will allow users to force iOS to clear system data. But, until then, this is the best iPhone users can do.
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