Storage very full with system and system data for some reason

iPhone storage is broadly divided into two important system-related categories: 

iOS and System Data.

iOS is the operating system itself—the files required to run your iPhone, including core system components, frameworks, and other essential software.

System Data, on the other hand, is a more general category. It contains various types of system-related files and temporary data that do not fit neatly into categories such as Apps, Photos, Videos, Messages, or Documents. This can include caches, logs, temporary files, Siri voices, fonts, software-related resources, and other data required by iOS and installed apps.

The size of System Data can fluctuate considerably. It may increase temporarily while you browse the web, stream videos, use apps, download content, install or update software, or perform other activities. Some of this data is eventually removed automatically when it is no longer required.

For that reason, I generally would not worry about System Data simply because the number appears large. iOS manages this storage dynamically and can reclaim or purge certain temporary and cached files when the device needs additional free space.

There is no universal "correct" size for System Data.

If System Data has grown unusually large and remains that way for an extended period, especially when your iPhone is running low on available storage, you can first try restarting the iPhone and allowing some time for iOS to manage the storage.

If the System Data remains excessively large and there is no obvious explanation, the most effective last-resort approach is to create a fresh, verified backup of the iPhone, then erase and restore the device. A clean restore can remove accumulated caches, temporary files, logs, and other residual system data that may not otherwise be cleared.

Before doing this, make sure your backup is complete. That important information—such as Photos, Messages, Contacts, Notes, WhatsApp data, and other app data—is either included in the backup or safely synchronised with iCloud or another service.

The more important figure is the available storage. If you still have plenty of free space, there is usually no reason to do anything at all. Let iOS manage System Data automatically.

System Data usually grows from caches. Try Settings > Safari > Clear History and Website Data, offload big apps you rarely use in iPhone Storage, and restart the phone. It sometimes shrinks after a day or two once iOS finishes cleaning up. If it stays huge, a backup and restore can reset it.

bartekmat47 wrote:

Hi, I have an issue with storage on my iPhone SE(2022). The space taken by system and system data is very large (more than half of the storage space). Is there any way to reduce that? The problem became serious after upgrading to iOS 26 from previous version in particular.

https://discussions.apple.com/content/attachment/6cb6c5af-dd33-41ec-a159-5d04ac701fcf

When System Data grows to abnormal levels, it's often because some corrupt data is there. Your phone only has 64GB, which in today's world is honestly woefully inadequate and there's no way to increase storage on an iPhone. It's unfortunate people overlook how incredibly important storage is. Today, all of Apple's newest iPhones come with 256GB as the lowest option. Personally, I now buy my iPhones with 512GB. You can never have too much storage. But you're seeing what can happen, when you don't have enough. When you buy your next iPhone, don't buy the lowest storage level available. Buy the most storage you can afford.

That said, you may be able to reduce System Data by restoring your iPhone from backup. The best method is to use your computer, but this link offers the methods you can restore your phone from backup --> https://support.apple.com/en-us/118105