On the average iPhone, the "Other" or "System Data" category quietly occupies 10 to 25 GB — more than most app libraries, more than years of text messages, and more than almost anything a user consciously put there. It sits at the end of the storage bar as a fat gray block, and Apple has never explained it particularly well.
You can't nuke it in a single tap. But with the right approach, most people recover 5–10 GB without deleting a single photo or app they care about.
What's Actually in That Gray Bar
"System Data" (the name Apple uses in iOS 16 and later — older iPhones still show it as "Other") is a catch-all for anything iOS doesn't categorize neatly under Photos, Apps, or Media:
- Safari cache — every page you visit gets stored locally for faster reloading
- iMessage media cache — link previews, GIF thumbnails, and inline photos from every thread, going back years
- Siri voice model downloads — a few hundred MB each, pulled automatically when you change Siri's language or voice
- iCloud sync temp files — created while Photos, iCloud Drive, or iCloud Backup does its thing
- Streaming app buffers — Spotify, Netflix, Apple Music, and podcast apps keep local playback data
- System logs and crash reports — iOS accumulates these quietly in the background
None of it is faked or wasted — it all exists for a reason. The problem is that none of it cleans itself up, so it compounds year over year on a phone that's in constant daily use.
1. Clear Safari Cache First
This is almost always the fastest win. Go to Settings > Safari > Clear History and Website Data, then confirm. On a phone used daily for a year or two, this typically reclaims 1–3 GB in under ten seconds.
The tradeoff: you'll be logged out of websites and your browsing history disappears. A mild inconvenience that's absolutely worth it. Do this before anything else on the list — it takes 30 seconds and it almost always produces a visible result.
2. Shorten iMessage History
Go to Settings > Messages and find Keep Messages. The factory default is Forever, which means every link preview, sticker, and reaction emoji from every group chat since you set up the phone is still in storage.
Change it to 1 Year. iOS will ask if you want to delete older messages immediately — say yes. Active group chats with heavy GIF usage can accumulate 500 MB to 2 GB over two to three years. Most people never look at this setting, which is exactly why it's so effective.
If you're comfortable with it, 30 Days is even more aggressive — but 1 Year is a reasonable middle ground for most people.
3. Delete Streaming Downloads You've Forgotten About
Open Spotify, Apple Music, Netflix, and any podcast app. Each has a downloads section — look under Library or Settings inside the app. These apps never auto-delete your saved content; they keep it until you manually remove it.
A single 4K Netflix film runs 2–4 GB. A few downloaded albums on Spotify add another 300–600 MB. If you downloaded something for a flight six months ago and never cleared it out, it's still sitting there.
4. Restart Your iPhone — Fully
This one sounds too simple. It isn't.
Go to Settings > General > Shut Down (not just pressing and releasing the side button — that puts it to sleep, not off). Let it power down completely, wait 20 seconds, then restart. iOS discards render caches, temporary download buffers, and system log queues on a full power cycle that sleep mode never touches. Check your storage immediately after — Other often drops 1–2 GB just from this step alone.
Many people haven't fully restarted their iPhone in months. That's months of temporary files accumulating.
5. Sign Out of iCloud, Then Sign Back In
Open Settings, tap your name at the top, scroll all the way down, and tap Sign Out. Wait about 30 seconds, then sign back in with your Apple ID.
Honestly, this feels like it shouldn't do much. It does. iOS rebuilds its local iCloud data from scratch after re-authentication, which discards stale sync caches — particularly the ones left over from old device migrations or iOS updates. People consistently report 1–3 GB freed from this step. It's one of the least-known fixes on this list.
6. Check Apps for Oversized Local Data
Go to Settings > General > iPhone Storage and tap apps one by one — particularly ones you haven't opened in a while. Each app shows two numbers: App Size and Documents & Data. When Documents & Data is several times larger than the app itself, that app is caching aggressively.
The usual culprits: mapping apps (offline maps), news apps, social media, and older productivity apps that cache documents locally. Offloading any of these clears the Documents & Data without deleting your account or settings.
EverClean AI can help you find duplicate photos and large videos in the same pass — since media bloat often travels alongside the same apps driving Other storage up. It's free to download on the App Store and runs entirely on-device.
After steps 1–4, most iPhones will show a noticeably smaller Other bar. If yours is still above 15 GB, you've either got a very active iCloud setup or app data that's genuinely hard to reduce without offloading. The last resort — Settings > General > Transfer or Reset iPhone > Erase All Content and Settings — brings Other under 5 GB guaranteed. Back up first.
For a broader look at freeing up iPhone space, see how to free up storage on iPhone and how to clear app cache on iPhone.