Tech Friend: iPhone ‘system data’ is hogging my storage

Tips & tricks
6 mins
Clear iPhone system data

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Beat the system

On my Apple devices, system data is always really high, at more than 15GB. I do not download things very often, but I do stream a lot of music. I monitor my storage, and none of the music services are taking more than 1 GB of storage, and my photos also take up less than 1GB.

I am constantly having to factory-erase my devices. On my iPhone 13 Pro Max, 29GB of storage is taken up, and only 5GB maybe is me, the rest is iOS and mostly system data. It is absurd. I’m perplexed about what to do. I feel someone is hogging my RAM. I can’t think of any other reason this could be happening.

Do you have any input you can add or wild ideas on why this continues on a daily basis and how to stop it? Thank you in advance.

Submitted by: Jay

So your iPhone is perilously close to running out of storage—seemingly all the time. While photos and messages are straightforward enough and easy to delete to free up more space, “system data” is not so obvious—and yet it tends to occupy a substantial portion of your phone’s storage.

A bit of background on how to check your iPhone storage (for our other readers). Head to Settings > General > iPhone Storage. You’ll see how much storage is being used and get a color-coded breakdown of the categories of data that your phone is storing.

iPhone system data full

In this example, “system data” is using well over half of the phone’s storage.

What is Apple system data?

According to iOS, system data includes “caches, logs, and other resources currently in use by the system.” Apple doesn’t specify what the data is but it generally consists of temporary files and other elements that don’t strictly form a part of an app’s storage. Apple also notes that this data will “fluctuate according to the system needs,” which means your iPhone should automatically remove system data when it is no longer needed.

As an example, even though Safari is an app, your Safari browsing history isn’t indexed as app data. It is saved as a cache file that gets indexed as system data. The same goes for downloaded content for offline playback on streaming apps like Spotify and Disney Plus. It seems like the “Apps” portion of the storage bar merely accounts for actual app size and “System Data” accounts for all temporary files and other data that don’t neatly fit into the other categories.

Here are what constitutes system data:

  • Cache: Caches are temporary files that speed up the performance of apps and websites. Data like your browser settings, offline content playback, location services, OS files, and even background app refresh add to the number of cache files stored on your device. If you have a lot of apps and websites you frequent, these files will quickly accumulate and take up a lot of space.
  • Logs: Your devices keep track of system events in the form of logs. System events can be anything from restarting your device, downloading apps, or changing settings. These logs are useful for troubleshooting when you run into problems with your device, but can also take up a lot of space. You also can’t remove them without a factory reset.
  • Other data: Other data that gets indexed as “System Data” could include downloaded fonts, voice memos, attachments, and offline translation languages.

Our best guess

It’s not really clear why these caches sometimes build up to take up most of a phone’s data and why it only affects some iPhones. Apple doesn’t break down what exactly is filling up “System Data,” making it hard to ascertain which system data elements are causing the issue. This makes it hard to address the issue. 

Based on your question, our best guess is that it is one of your music services. While the apps don’t take up a lot of storage, the cache for playing your music could be hogging a large amount of space. It could even be that one of your services has a bug or a problematic setting that’s making it do this.

To test this theory, you could check the cache size of each app (such as Spotify and Apple Music) within the app itself. You could also try only using one music app for a period, and maybe deleting the others temporarily, to identify the problematic app by process of elimination.

If you do identify a particular app that’s taking up your storage, you can simply stop using it or try examining its settings and turning off features.

How to clear system data on iPhone

As you confirm the root of the problem, in the meantime, you’ll want to clear your system data when it accumulates. We know from your question that you take the route of factory reset to get rid of system data. This is one way to do it—although it’s usually more of a “nuclear” option and can’t be very convenient. There are a few other, less drastic, measures to take.

  • Shut down your iPhone. Wait a few minutes before turning it back on. Doing so will free up system resources and clear temporary files from your storage. It’s a lot easier than a reset of your phone.
  • Clear cache in Safari. If Safari is your browser of choice, the cache can take up significant storage. Clear it by going to Settings > Safari > Clear History and Website Data
  • Delete offline content. Periodically delete offline content from your apps—such as downloaded shows in the Netflix app. You need to do this individually in the apps. Where possible, set them to auto-delete. 
  • Disable features. Apple devices and apps come with a lot of features, but you probably don’t need all of them. Disabling the ones you don’t use could help prevent the accumulation of system data. To disable features, click through your device’s settings menu and toggle off the ones you don’t use. Examples include the Translate app’s On-Device Mode (translates languages when you’re offline) and Apple Maps’ feature that knows where you parked.
  • Identify rogue apps. As mentioned above, try temporarily eliminating apps from your phone to determine if there’s one using an inordinate amount of system data storage. It’s detective work but it can save you hassle in the long run.
  • Finally… a factory reset. A factory reset followed by restoring your backup files is the surefire way to lower your system data. To do so, head over to Settings > General > Transfer or Reset iPhone > Erase All Content and Settings. If you do that, know that you will also be signed out of your Apple ID and all your apps, media, and personal data will be removed. 

Bonus: How to clear Android system files 

If you’re using an Android phone, you might be facing a similar problem with Android system files consuming too much storage. As with Apple devices, system data builds up when too many apps store temporary files. Thankfully, Android makes it easy to clear these files, which it automatically labels as “Junk Files.”

Here’s how to clear junk files on Android to free up some space:

  1. On your Android device, open Files by Google 
  2. At the bottom, tap Clean
  3. On the “Junk files” card, tap Clean xx MB
  4. On the confirmation dialog, tap Clear

The Files by Google app also lets you view all the files and attachments stored on your device. Sometimes, these files take up too much storage space, so click through the app and clear any file you don’t need. A word of warning, anything you delete on the Files by Google app can’t be recovered, so if you’re not sure if a file is essential for your device to work, it’s best to leave it.

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