On iOS 18 the old "Other" category is now labelled System Data, and you shrink it by clearing app caches, deleting Safari website data, removing a stuck software-update file, and restarting the phone. You cannot delete System Data directly — there is no button for it — but those steps reliably bring it down, often by several gigabytes.
TL;DR
- "Other" is now System Data in Settings > General > iPhone Storage.
- It holds caches, logs, streaming buffers, Siri voices, and update files — not your photos or apps.
- There is no "delete System Data" button; you shrink it indirectly.
- Biggest levers: clear Safari data, offload heavy apps, delete a downloaded iOS update, restart.
- A few GB of System Data is normal; 20–50 GB usually means a cache that will not clear itself.
What is "Other" / System Data on iPhone?
It is the catch-all bucket for everything that is not a photo, app, message, or media file: system and app caches, logs, Siri and dictation assets, streaming video buffers, and partially-downloaded updates. It exists so apps load faster and iOS runs smoothly. The problem is that iOS does not always prune it, so on a phone you have used for a year or two it can balloon well beyond what is healthy.
How do I see how big it is?
Open Settings > General > iPhone Storage and wait for the bar to load. The grey System Data segment sits at the right of the bar; scroll to the bottom of the list to see its exact size. A few gigabytes is normal. If it is 20 GB or more, the steps below are worth doing.
How to shrink System Data safely
Work through these in order and re-check the storage screen after each:
- Clear Safari website data — Settings > Apps > Safari > Clear History and Website Data. This alone often removes the most.
- Offload heavy apps — Settings > General > iPhone Storage > [app] > Offload App. This clears the app's cached footprint while keeping your documents and data.
- Delete a stuck iOS update — if an update downloaded but did not install, tap it in the storage list and choose Delete Update; it can be several gigabytes.
- Clear streaming and chat caches — inside Netflix, YouTube, Spotify, WhatsApp, and Telegram, clear downloads and cache from each app's own settings.
- Restart the iPhone — a restart forces iOS to flush temporary files and recalculate storage.
What iOS does natively, and where it stops
iOS quietly trims some caches and offers Offload Unused Apps (Settings > App Store > Offload Unused Apps), but it gives you no direct control over System Data and no view of what is inside it. That opacity is the frustrating part — you are clearing caches blind. A cleaner cannot open System Data either, but it can remove the inputs that feed it fastest: large cached media, duplicate photos, and heavy videos.
What this cannot do
You cannot manually delete System Data, and a full reset (erase and set up as new) is the only way to zero it — which is overkill for a storage problem. The steps above are the safe ceiling; if System Data refuses to drop below ~10–15 GB after all of them, it is usually iOS holding caches it will clear on its own over the next few days.
FAQ
Where did "Other" storage go on iOS 18?
Apple renamed it System Data. It is the same category — caches, logs, and system files — shown at the right end of the bar in Settings > General > iPhone Storage.
Can I delete System Data directly?
No. There is no delete button. You reduce it by clearing Safari data, offloading apps, deleting a stuck update, clearing app caches, and restarting.
Why is my System Data 50GB?
Usually a runaway cache — most often Safari website data, streaming downloads, or a failed update file. Clear those and restart; it should fall sharply.
Will clearing System Data delete my photos or apps?
No. System Data does not include your photos, messages, or installed apps — only caches and system files that rebuild as needed.
For the bigger picture, read what System Data is on iPhone and Android and iPhone storage full but nothing to delete. To clear the heavy media that feeds System Data, get Cleanor for iPhone or start with the free up iPhone space guide.