Guides

What Is System Data on iPhone, and Can You Shrink It?

Updated October 28, 2026 · Written for iOS 26

You open Settings > General > iPhone Storage, scroll to the bottom and find System Data taking 15, 25, sometimes 40 GB. There's no delete button. Here's what is going on.

What's in System Data

System Data (it used to be called "Other") is everything iOS stores that doesn't belong to a single app you can see in the list. That includes:

• Caches from streaming music and video
• Logs and diagnostic files
• Temporary files from updates and downloads
• Siri voices, dictionaries, offline translation languages and fonts
• Parts of Safari's website data

It grows and shrinks on its own. iOS clears caches when the phone runs low on space, so a big number isn't necessarily a problem. It becomes one when it stays big and your phone keeps telling you it's full.

Why no app can clear it

iPhone apps run in a sandbox. An app can see its own files and, with your permission, your photos or contacts. It cannot see or delete files that belong to iOS or to other apps.

So when a cleaner app promises to "clear junk files" or "clean system storage", that's not something iOS allows it to do. Be wary of any app that claims it can, especially one that wants a weekly subscription for it.

What you can actually do

These are the things that tend to work, roughly in order of effort.

1. Restart your iPhone

Hold the side button and a volume button, slide to power off, wait 30 seconds and turn it back on. A restart often clears temporary files. Check iPhone Storage again afterward.

2. Clear Safari's website data

Go to Settings > Apps > Safari > Clear History and Website Data. This signs you out of websites, so have your passwords handy.

3. Remove offline languages and voices you don't use

Check Settings > Apps > Translate for downloaded languages, and look under Settings > Accessibility > Spoken Content > Voices for extra voices you may have downloaded.

4. Let streaming apps clear their caches

Apps like Spotify, YouTube and Netflix keep downloads and caches. Most have a setting for this inside the app. Deleting downloads in those apps is usually faster than waiting for iOS to do it.

5. Free up space elsewhere and wait

iOS clears System Data more aggressively when space is tight. Freeing a few GB in Photos or Messages and leaving the phone on charge overnight often makes System Data drop too.

6. Last resort: back up and restore

If System Data stays enormous for weeks, a backup and full restore resets it. Back up to iCloud or a computer, then go to Settings > General > Transfer or Reset iPhone > Erase All Content and Settings, and restore from the backup during setup. This takes an hour or more, so only do it if nothing else has worked.

Where the space usually is

For most people, System Data isn't the main problem. Photos and videos are. If your phone is full, check the top of the iPhone Storage list first. Our guide iPhone Storage Full? What to Delete First walks through it in order.