How to clear System Data on iPhone

What System Data is

Open Settings > General > iPhone Storage and scroll to the bottom of the list. Below your apps sit two entries you cannot open in the usual way: iOS itself, and System Data. Apple's storage article describes this area as space for things like non-removable logs and caches, the Spotlight search index, Siri voices, fonts, dictionaries, and system records such as the Keychain and the CloudKit database.

Much of it is temporary. Streaming apps buffer video into caches, Safari stores pieces of websites, Messages keeps previews, and iOS writes logs as it runs. Apple's guidance says these cached and temporary files are removed when the device needs more space. That is why System Data can look huge one day and shrink the next without you doing anything.

The size varies by model, iOS version and how you use the phone. A figure that seems large is not by itself a sign that something is broken.

Steps that actually shrink it

1. Restart the iPhone. A restart clears some temporary files and forces the storage screen to recalculate. Wait a minute before reading the bar again.
2. Clear Safari's website data. Go to Safari's settings (under Settings > Apps on recent iOS versions) and tap Clear History and Website Data. This signs you out of websites, so have your passwords ready.
3. Check apps that download a lot. Video, music, podcast and map apps keep offline files and caches. Open each app and remove downloads you no longer need, or delete and reinstall the app to drop its cache.
4. Trim Messages. Long threads full of videos and voice notes add up. Our guide to large message attachments shows where they hide.
5. Install iOS updates. Leftover update files sometimes linger until the next update completes.
6. Leave it on the charger overnight. Some housekeeping happens while the phone is idle and connected to power.

The last resort, erase and restore

If System Data stays unusually large after all of that and the phone is struggling for space, some people back up, erase the iPhone and restore from that backup. Restoring brings back your apps, messages and settings, while many old caches are not carried over.

This is a big step, so treat it carefully. Make a complete backup first and confirm it finished. If you use iCloud Photos, check that your library has fully uploaded before you erase anything, and keep a second copy of irreplaceable photos on a computer or drive. Our guide on how to back up iPhone photos walks through the options.

Before going that far, look at the rest of the storage list. Photos, videos and message attachments are usually far larger than System Data, and they are the part you can clean up directly. The check your storage guide explains how to read the list, and freeing up iPhone storage covers the biggest wins.