iPhone Won't Update iOS 18: 4 Effective Solutions

Sometimes, you may find your iPhone can't update to iOS 18. Don't worry, this post will provide 4 effective methods to help you out of iPhone 14/15 won't update issue.

By @Dylan Last Updated September 4, 2024
 

My iPhone can't update to iOS 18.

Hi, I'm just wondering if anyone can explain why my iPhone 14 can't update to iOS 18. I'm using iOS 17.5 now. I just received a check error when I tried to manually update it. What should I do?

- Question from forums. macrumors.com

Why iPhone won’t update iOS 18?

Apple keeps releasing new iOS versions to add more features on iPhone and make iPhone more stable. But sometimes, some users reported that they can't update their iPhone to the latest iOS version. For example, the process just stuck in the middle, or an iPhone fails to download the package, and so on.

There are various causes making an iPhone unable to update, The most common reasons include weak network conditions, not enough space on the iPhone, the iOS package is corrupted, etc. If you encounter this issue, don't worry, just follow the next part, we summarize some solutions and guide you on how to fix this problem in detail.

How to fix iPhone won’t update to iOS 18

Before we try to fix this issue, please make sure the Automatic Updates option is enabled. Go to Settings > General > Toggle on the Software Update option.

In addition, please backup the iPhone in case of any unexpected issues because of incorrect operation.

Method 1. Check Network and battery level

iOS update can take dozens of minutes, so it needs a stable and strong Internet connection and at least 50% of battery level to download and install the iOS 18. So, we suggest you perform this process at home because usually the updating won't be interrupted by weak network/Wi-Fi or low battery level.

Please connect your iPhone with a charger if the battery level is low. And you can connect a Wi-Fi to make sure the network conditions, you can just go to the Settings app > Tap Wi-Fi > Choose a trusted and powerful Wi-Fi.

Method 2. Free space on the iPhone

If your iPhone is running out of space, it can't download iOS update files. Although iOS 18 comes in size with around 2 GB to 3 GB. But you will need to make sure at least 6GB of available space to complete the installation and guarantee stable running.

In this case, you can go to Settings > General > iPhone Storage to see how much available space is on your iPhone, and delete some apps.

Then you can tap an app that takes up large space on your iPhone, and delete it. If you want to keep the app, just back to the Home screen and run this app, and go to settings of it, usually you can clear the cookies or history there.

Some users might have a large number of media files, like photos, videos, etc. you can go to the Photos app to delete some of them. And if you don’t want to lose them, you can transfer photos from iPhone to a computer.

Method 3. Update iPhone via iTunes

iTunes can be an alternative tool when your iPhone fails to update. When iTunes detects your iPhone on a PC, it will receive a notification to update iPhone. Just follow the guide below:

1. Download and install iTunes. And connect iPhone to a computer with a USB cable.

2. Click the phone-like icon to enter the Summary tab.

3. Click Update. The package for upgrading iPhone would be saved to the computer and you could decide when to upgrade iPhone.

Method 4. Redownload the iOS package

If the downloading process was interrupted for some reason, you may have a corrupted package. The iPhone would tell Unable to Check for Update or Unable to Verify Update, you can delete the iOS package and redownload it to fix the iPhone won't update problem.

To delete the iOS package: Just go to Settings > General > Storage.

Download the package: Go to iPhone Settings > General > Software Update.

Additional content: Protect iPhone data before updating iPhone

Before upgrading iPhone, you should save iPhone data to a safe place to avoid any damage to your data. Although new iOS could fix some problems in the previous version, it also brings new problems. For example, some users reported that they lost photos after upgrading iOS.

You could use AOMEI FoneBackup to quickly save iPhone data. It is a free professional iPhone backup software. You could use it to backup iPhone contacts, messages, music, and videos to computer in seconds.

3 Steps to save what you want to computer

Step 1. Download AOMEI FoneBackup. Connect iPhone to computer with USB cable and tap “Trust” on it.

Download Freeware Win 11/10/8.1/8/7/XP
Secure Download

Step 2. Click Selective Backup. Click an icon to select what you want and click OK to return.

Step 3. Click Start Backup to start the process.

⚠️Note:
  • You can also choose Full Backup on the main interface to completely back up your iPhone.

Conclusion

Hope the post can help you out of the "iPhone won't update" issue. You can check your network, update with iTunes, free up some space, or redownload the installing package to solve iPhone 14/15 unable to update to iOS 18. And remember to save photos and other data in a safe place.

If you are using really old model, please check the supported models of the iOS version. For instance, iOS 18 is not compatible with models older than iPhone XR.