Apple

I find it really annoying too. Unfortunately this has been a thing since the earliest apple devices. Back then it was called "Other" and not much besides the name change has improved. You'd think that apple would add a way to clean it manually but no, probably in the next decade.

With modern devices having a minimum of 128gb it's not usually a problem in daily usage though. Only when it shoots up to many tens of GB then you can do the date trick.

If you temporarily set the date a few years in the future and wait a bit, the system will try deleting the cache. Just be careful of expiration for SMS chats.

Just as well Apple doesn’t charge a premium for storage space ✊💦💦💦

This happened to me and it ended up being the mail app.

Do you need this space right now? It should free it up automatically if space is tight.

I've found it to happen when an app schedules something for deletion, but the OS doesn't get around to actually completing the deletion operation for one reason or another. A normal restart seems to fix it up for me.

YMMV, but this problem went away for me when I disabled syncing to my MacBook via WiFi. My guess is that it was caching backup images but never successfully copying and removing them.

Apply the trick of flight mode and forward 1 year in system date

When I had the problem on my wife's phone, the answer ended up being text messages and safari. This was 5 years ago so I don't know if it changed but despite the apps saying it used x storage under storage, it was actually kept in System.

Is your phone out of storage?

This value will fluctuate according to system needs

iOS might wait to purge the cache until it needs the space

Wow I just checked and mine is at 25gb on iPhone 13, so no AI stuff.

Metadata, caches, obsolete files and stuff, uncleaned leftovers from miscellaneous apps, out of sync forgotten bytes, and the Ghost in the machine…

Work computer recently had 400gb of 500 filled with system data stuff. /Tmp doesnt get cleaned except for on reboot.

The advice I’ve seen is to back up your phone (iCloud or iTunes), factory reset, then restore your backup.

These things get bigger and bigger the older your phone is, because OS updates seem to always leave more and more shit laying around (probably for disaster recovery in case the update goes sideways).

Windows has a command you can run to purge all the old update shit to free up space. I wish Apple would get off their ass and implement the same.

I don't like the lack of a meaningful explanation. "System Data" might as well be "stuff" and I don't trust it.

Then again, Apple is known for their toddler-compatible interfaces. Maybe they thought that an actual explanation or breakdown would be too complicated and scary for their average user.

Do a factory reset. Mine got up to 30GB. I did a factory reset and now it’s at 8GB

A big chunk of that is probably on-device AI models that shareholders demand Apple force on its customers to demonstrate that they’re not being left behind.

Lol mine is 20 GB. And iOS takes 12.5GB. Thankfully I got the 256GB model, use Immich to backup images and videos, use Paperless-ngx for storing my docs and know how to use and manage a filesystem (however shitty it is on iOS) unlike most normies who would just let everything pile up and get confused on why there is no C: drive on iOS (real story lol).

Im not endorsing it, but It makes more sense when you realize that the difference between the different Apple OSs is only the UI. They are all the same OS called Darwin. They have gotten sloppy about the optimizations between devices since they started spinning their own silicon.