iPhone system data filling up device after iOS 26 update

I had this problem too with the upgrade on my iPhone 12 Pro Max.

One of the thing that seems have solved it is to disable the automatic download of new system updates (General-Software Update) because iOS was reserving space for them (almost 12 GB).

"iPhone system data filling up device after iOS 26 update: [...]I ended up backing up the device, wiping it, and restoring it from backup and I noticed that i had about 60GB of space free. [...]Can anyone give me some advice here?"

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To the OP and All those Affected:

A. Properly Clearing System Data After an Update:

The erasure between the backup and then restore may be the issue here, as it is not a required step In this process. Here is my User Tip on how to clear of the System Data: How to Clear "System Data" in your iPhone's Storage: - User Tip

B. Report this Bug to Apple:

Do your Part: These are user-to-user forums. Apple rarely reads these forums on their own time as it is. So, provide Apple with feedback on this.  Apple wont get back to you directly, but the more they hear of this, the more they will know what is going on, and what needs to be fixed.

To Provide Feedback:

1. Go Here: Feedback - iPhone - Apple
2. Select: "Bug Report" for the "Feedback Type"
3. Comment: when this all began, and how you have troubleshot this thus far. Include the URL of this thread.
4. Proceed form there as necessary

• Restart the device. That's it.

If the above does not resolve the issue then...

I would ignore that because this system data will make room when you need more space on your iPhone. These are some cache and temporary files that will be erased by the system whenever you try to save more files.

You may --> Clear Other storage on your iPhone or iPad - Apple Support (IN)

Tap on System Data it will take you to "Other System Data"

Now the question is what is the "Other System Data" storage. Read on...

• Other System Data: Non-removable mobile assets, like Siri voices, fonts, dictionaries, non-removable logs and caches, Spotlight index, and system data, such as Keychain and CloudKit Database. Cached files can't be deleted by the system.
• System: Space taken by the operating system. This can vary based on your device and model.

About cached files in "Other System Data"

Finder and iTunes categorize cached music, videos, and photos as Other instead of actual songs, videos, or photos. Cached files are created when you stream or view content like music, videos, and photos. When you stream music or video, that content is stored as cached files on your device so you can quickly access it again.

Your device automatically removes cached files and temporary files when your device needs more space.

If storage on your device differs from what you see in Finder or iTunes

Since Finder and iTunes categorize cached files as Other, reported usage for Music or Videos might differ. To view usage on your device, go to Settings > General > [Device] Storage.

If you want to delete the cached files from your device

Your device automatically deletes cached files and temporary files when it needs more space. You don't need to delete them yourself.

I spoke to an Apple representative last week and followed her instructions. She advised me to back up my iPhone first, then wipe it using a Mac to clear the system data correctly. After that, I set up the phone as a new device.

To do this, I plugged the iPhone into the Mac, put it into recovery mode by pressing the volume up and down buttons, and then pressed and held the side/power button until the USB cable pointed towards an iTunes/Finder logo.

I then restored my iPhone from my backup. I’ve done this twice since, but I’m still experiencing the same unresolved issue.

I hope that the rumored iOS 26.2.1 release will fix it. Apple knows about this issue because the representative mentioned that our issue is known.

I expect iOS 26.3 and iOS 26.2.1 to be released soon, and I hope for some relief.

“[…]But since iOS 26, iPhone keeps Running: out of Memory and the System Data keeps Ballooning, After Restoring Multiple Times, and Multiple Calls to Apple. if anyone gets a Resolution, Please Post it.”

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Clearing System Data in a Loop After Update:

A. Use my User Tip:: How to Clear "System Data" in your iPhone's Storage: - User Tip

B. Reset to Factory Settings:

If still getting this issue, you may need you backup your iPhone to a computer, and then reset it to Factory Settings. Look into taking a few screenshots, and then email them to yourself, as a way to remember what when where, and how things were configured. Enabling Items in iCloud (ie Photos and Messages), you can back them up, if you have free storage to do so.

“Same issue with me. Does anyone know if iOS 26.3 fixes this? How about putting the phone in recovery mode, then restoring iOS 26.2?”

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Clearing Caches:

You should perform my User Tip : How to Clear "System Data" in your iPhone's Storage: - User Tip

Same issue with me. Does anyone know if iOS 26.3 fixes this? How about putting the phone in recovery mode, then restoring iOS 26.2?

I have the exact same problem with my iPhone 15 Pro 256GB version. I had more than 130GB of free space but after updating to iOS26 the system data started filling up any empty space.

I cant even receive emails now!

Apple please fix this as it must be some kind of bug.

Same problem for me. It’s killing my iPhone 15 Pro. 64GB of system data and even if I delete apps it keeps filling the space. Wiped and restored, plenty of space, then 2 weeks later it’s back up to full. Apple please fix this ASAP. My phone is becoming useless. And, please provide users more control and visibility over system data so we can see what is going on.

Yep. Back to full. Disappointed. Like you I will have to do this every two weeks. Productivity killer so I hope it get fixed soon. It’s brutal. iOS 26.1 Beta 4 is available but I haven’t tried it. Need to wipe my phone again to make space.

[HELP HELP HELP]

I am Having the Same Issue.

iPhone 15 Pro Max with 90GB Free on iOS 18.7, with no issues at all.

But since iOS 26, iPhone keeps Running out of Memory and the System Data keeps Ballooning,

After Restoring Multiple Times, and Multiple Calls to Apple.

if anyone gets a Resolution, Please Post it.