Major Storage Bug After iOS 26 Update — Losing Dozens of GB for No Reason

To resolve this issue, you can backup to a Mac and then erase your iphone and restore from the backup. If you don’t have access to a computer (it can be done on windows too), backup your iphone to iCloud, erase your device and then restore from your iCloud backup.

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

JerBear61 wrote:

Why should we have to back up and erase all contents and data. Why can't Apple just resolve this issue in one of their updates, perhaps maybe iOS 26.2? This is "System Data" bloating our devices after all. I don't see why we need lose our data off devices we use everyday. This is on Apple to fix

There's no way to resolve an issue like corrupt data in System Data via a software update, which is most often the cause of bloated System Data. Apple has no access to the data on your phone. Further, the data on your phone is fully encrypted. This is also not a system wide issue, meaning the vast majority of users don't have any corrupt data in System Data. But for someone who does, a backup/restore will fix it. So that's why you have to do this. Or live with the issue, which doesn't seem like a very optimal solution.

A final note: If system data is causing issues because it has grown too much, then the user doesn't own a phone which meets their storage needs. Once purchased, iPhone Storage is fixed and can never be increased. People often don't pay enough attention to how much storage they will need, not just when they get a new phone, but what their storage needs may be over the long haul. Here, on this forum we recommend buying a phone with the most storage someone can afford.

JerBear61 wrote:

Yeah I had to eventually erase all data but I still don’t understand why that’s necessary. Why can’t they just fix whatever cache bug is causing their OS to bloat devices?

If System Data becomes bloated, it's always because you have some corrupt data. Data, which is on your phone only. Most people don't get any corrupt data. But if you do, the ONLY want to remove it is to restore your phone and that isn't something Apple has any ability to control for you.

I e read- not verified that if you do the update via ov using iTunes it can actually reduce cache, possibly from prev updates ( we’ll never know).

others have said they did the iTunes connection and that reduced there storage used by updates significantly as well.

I can’t say whether this is enabled for you or not, but my iPhone 15 dropped from 15GB to 5GB after the update to 26.1. Nothing I was doing was fixing the problem, deleting around 4-5GB of music did nothing either.

I really didn’t want to wipe the phone and start anew either so was just dealing with it. Today I took my wife off of our shared iCloud storage and we now pay for separate storage and all of a sudden 12GB came back. It seemed like some type of phantom cache bug or something, didn’t make any sense to me at all since that’s the only thing that changed.

I now have 18GB free. It’s still not acceptable to me but maybe this will help someone else.

Can you get external storage port - thumbnail storage that’s compatible with Apple connection and move anything there?

you can offload apps saving storage temporarily.

You can remove Google photos. When you reload it it’s the same because it’s saved to your google acct… don’t delete your google photos acct, just the app.

you can go a backup via Mac/pc using iTunes connection. This has cleared other/past updates caches for people.

ios 26 needs the space to download and mostly to install. It only 7 gb. It’s supposed to delete old iOS programs, updates, etc, as in. replace with the 7 gb iOS 26.

Seems different people do it differently so they have different results. Best results reported using Mac/ pc iTunes connection and move.

Yeah I had to eventually erase all data but I still don’t understand why that’s necessary. Why can’t they just fix whatever cache bug is causing their OS to bloat devices?

When I click my initials at the top right of “Collections” in the photo app, it says my name then “[# of] photos, [# of] videos, [# of] items

restoring…”

each photo takes up 2-3x as much space as it did before I installed iOS 26.1 by the way also

Pay a couple of bucks a month, (or half a cup of Starbucks) then turn on iCloud Photos with optimised storage, that way you get more space.

So I had this issue a few months ago, right. My issue was with Apple Maps. I had over 10GB of data, even the gent at the store laughed like “what on earth?”.

He told me to restore from back up. I went home and searched a Reddit and LOADS of people had the same issue.

I ended up deleting a bunch of random apps and updating from ios18 to 26.

Problem solved!

Now it’s with system data. This btw everyone, is data we cannot preview. Something isn’t 100% right here…

Apple always come in with the classic “back your photos up and restore from backup”.

But this is two iOS versions with the same issue? I really want to know what goes on in the iOS HQ! Same mistake twice and it’s a BIG one! Absolute jokers 🤣

Did you attempt to backup to your computer as was recommended?

In the same situation

Hopefully, we can have a solution can’t back up because there is no storage yet there is storage

Please, Apple resolve this!!!

My partner’s in graduate school and is not able to get to her papers after spending two grand on a Mac

We need this resolved now, so hopefully some technician from apple can give us a solution or an update

Carlb4u wrote:

In the same situation

Hopefully, we can have a solution can’t back up because there is no storage yet there is storage

Please, Apple resolve this!!!

My partner’s in graduate school and is not able to get to her papers after spending two grand on a Mac

We need this resolved now, so hopefully some technician from apple can give us a solution or an update

You aren't speaking with anyone from Apple here. This is a user to user only forum, which no one from Apple participates, nor reads for user feedback. I don't understand what your partner's Mac has to do with iPhone. Did you mean to post on the Mac Forum, if he's having an issue with his Mac?

pickleprincess wrote:

I appreciate the suggestion, but that’s actually part of the problem: I can’t back up my iPhone because there isn’t enough free space left to even start the backup process. Every time I try, it says “There isn’t enough free space on this device to finish a backup.”

So I’m basically stuck in a catch-22: I don’t have enough storage to make a backup, but I need a backup in order to erase and restore my phone. I’ve already deleted almost everything possible: videos, photos, apps, offline music but the storage never changes. My System Data is taking up over 32 GB, and it won’t go down no matter what I do.

This update has completely trapped me in a loop with no way to fix it. I shouldn’t have to erase my entire phone and risk losing data because of a system bug that came with iOS 26.

If you are using iCloud Photos you can turn if off to free off some space.

Similarly uninstall space hoggers like Youtube or Whatsapp, then do the backup and restore.

Turn iCloud Photos back on