In Settings > General > iPhone Storage, the grey section at the end of the bar is System Data (older versions of iOS called it Other). It often uses several gigabytes and can fluctuate from day to day.
What System Data contains
System Data is a catch-all for data that does not belong to a specific app or category, including:
- Caches that iOS and apps create to work faster.
- Logs and diagnostic data.
- Temporary files used during updates, downloads and streaming.
- Downloaded resources such as Siri voices, fonts and dictionaries.
iOS manages this data automatically and removes caches and temporary files when it needs space. That is why the number goes up and down.
Safe ways to reduce it
Restart your iPhone
Many temporary files are cleared on restart. Restart, wait a few minutes, then check iPhone Storage again.
Update iOS
Go to Settings > General > Software Update. Installing a pending update removes downloaded update files and can fix bugs that cause caches to grow.
Clear Safari data
Safari's cache and website data can be counted partly in System Data. Go to Settings > Apps > Safari > Clear History and Website Data. See clearing the Safari cache on iPhone.
Trim Messages
Large Messages histories and attachments can contribute. Review attachments in Settings > General > iPhone Storage > Messages and consider setting Keep Messages to 1 year. See reducing Messages storage.
Reinstall apps with large caches
Some apps, especially social media and streaming apps, keep large caches that are not cleared on their own. Check an app's Documents & Data size in iPhone Storage. If it is much larger than the app, delete the app and reinstall it from the App Store. Make sure your data in that app is synced or backed up first.
Free up space and let iOS clean up
When storage is very low, iOS automatically removes caches and temporary files. Freeing space elsewhere can let it work more effectively. See freeing up iPhone storage.
Last resort: back up and restore
If System Data stays enormous after all of the above, backing up your iPhone, erasing it and restoring from the backup rebuilds the data from scratch. This takes time and should only be done with a confirmed, complete backup.
What not to do
There is no way to delete System Data directly, and apps claiming to "clean" iPhone System Data cannot access other apps' data on iOS. Be cautious of anything that promises otherwise.
Frequently asked questions
Why is iPhone System Data so large?
It includes caches, logs, temporary files and downloaded resources. Large Safari or app caches, Messages and pending updates are common causes.
Can I delete System Data on iPhone?
Not directly. Restarting, updating iOS, clearing Safari data and reinstalling apps with large caches are the safe ways to reduce it.
Is System Data the same as Other on iPhone?
Yes. Older versions of iOS labelled this category Other.
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