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iPhone Won’t Update to iOS 15 (8 Easy Fixes)

author Carrie Murray
date Wednesday, September 29, 2021

Things may seem complex when you try to fix the iOS update problems by yourself. If you are afraid of misoperation or have no idea what to do by yourself, using a third-party iOS system recovery program is a great alternative, for example, FonePaw iOS System Recovery.

Along with the widely anticipated launch of iPhone 13, iOS 15 also finally came to everyone’s sight and was released on September 20. This new iOS system boasts multiple new features that can dramatically improve your experience during daily use and communication, like the Focus Mode, Live Text, FaceTime new functions, etc. However, you may have tapped the “Software Update” and find something wrong happened. Problems sometimes arise when there is an iOS update. What can we do when iPhone won’t update? Scroll down to see.

Part 1. How to Fix iPhone Won’t Update Problems

iPhone won’t update problems can be caused by different reasons and the fixes also vary. Here we provide 8 ways for you to try as well as to avoid data loss during the iPhone update, from basic methods to advanced ones.

1. Make sure your iPhone is compatible with the latest iOS update

Before you update your iPhone, remember to check if the new iOS system is compatible with your device. As listed on Apple’s website, the iOS 15 update supports the iPhone model which is iPhone 6s/ iPhone 6s Plus or later. That is to say, if your iPhone is newer than iPhone 6s/ iPhone 6s Plus which were introduced in 2015, theoretically it can be updated to iOS 15.

On the contrary, if your iPhone is an old model, it’s a pity that you cannot do the update due to the incompatibility. However, you are recommended to take the minor updates in the current system which usually include security improvements.

2. Make sure your iPhone storage is available

iPhone update failure can be caused by insufficient storage space. The iOS 15 update requires at least 3.2 GB of free space to download the update file. But usually, it needs more space for installation, so 10 GB storage space is recommended.

If there is not enough space on your phone, you can check your storage at Settings > General > iPhone Storage and manage the space to make it available for iPhone updates.

Check iPhone Storage

3. Make sure your iPhone is connected to the Internet

Internet error can also cause iPhone won’t update problem. There are three ways to enable and check your network for iOS 15 update.

  1. Go to Settings > WLAN > Enable your Wi-Fi network if you haven’t turned on.

  2. Go to Settings > WLAN > Apps Using WLAN & Cellular > Enable your network for Settings if it shows “Off”.

  3. Tap Settings > General > Reset > Reset Network Settings if the previous two ways don’t work.

Reset Network Settings


1. Using Wi-Fi to update iPhone is preferred over using cellular data because it’s usually more stable, takes less time, and does not cause extra charge.

2. If your iPhone cannot update in one network, try to switch to another one. It may work.

4. Restart or force restart your iPhone

If your iPhone still encounters update problems after the basic settings, such as stuck in a process, no reaction, frozen screen, etc., try to restart or force restart your iPhone to fix some system errors.

How to restart your iPhone

  • If your iPhone is iPhone X or newer: press and hold either volume button and the side button simultaneously, and then “slide to power off” accordingly. After the shutdown, long press the slide button to turn on the phone.

  • If your iPhone is iPhone 8/ iPhone 8 Plus or older: press and hold the side button (For iPhone SE 1st generation, it is the top button) and wait for the power off slider to appear. After the shutdown, long press the side button (or the top button) to turn on again.

How to force restart your iPhone

  • If your iPhone is iPhone 8/ iPhone 8 Plus or newer: press and quickly release the volume up button, then do the same to the volume down button, and then long press the side button until the Apple logo appears.

  • If your iPhone is iPhone 7 or iPhone 7 Plus: press and hold the volume down button and side button at the same time until the Apple logo appears.

  • If your iPhone is iPhone 6s or iPhone SE (1st generation): press and hold the side button (or top button) and the Home button at the same time until the Apple logo appears.

Force Restart iPhone X

5. Manually upgrade to iOS 15

If your iPhone cannot update to iOS 15 automatically or is stuck in verifying installation, try to manually process the upgrade.

How to manually download/ install iOS 15

  1. Go to Setting > General > Software Update. Often there is a notice in red telling you that there is an iOS update available.

  2. Tap “Install Now” to start updating.

Manually Upgrade iOS


1. Once you have turned off the “Automatic Updates”, your iPhone won’t update itself until you download and install it manually. You can turn on “Automatic Updates” for the automatic download or both download and install next time.

2. Because iOS 15 is a level-up update, for iOS 14 users, you can choose to upgrade to iOS 15 or just launch iOS 14.8 update and keep it in your current iOS version.

How to manually delete the update file and reinstall it

Things may happen like your phone showing that it fails on your update verifying and it doesn’t work when you keep tapping “Retry”. At this time, you may have downloaded the iOS update file and there is something wrong with it. Try to delete it and download the update file again.

  1. Tap Setting > iPhone Storage.

  2. Find out the update file with a gear icon in the apps below.

  3. Select the file and choose “Delete Update”.

  4. Go back to Setting > General > Software Update to reinstall iOS 15.

6. Upgrade to iOS 15 with a computer

If you fiddle with your iPhone again and again and it still fails to update, there is still a way: upgrade your phone to iOS 15 with a computer.

The computer can be Windows or Mac. For macOS 10.15 or later, you can use Finder to upgrade. For macOS 10.14 or older or Windows system, iTunes will be available for the update.

Here we will take using iTunes as an example, and the way using Finder is similar:

  1. Launch iTunes (newest version).

  2. Plug your iPhone into the computer. Using the original charging cable to connect is recommended.

  3. Select the iPhone icon.

  4. Click “Check for Update” to find iOS 15 update.

  5. Click “Download and Update” to install iOS 15 for your phone.

Check for Update in iTunes

7. Reset or restore your iPhone for update

Unfortunately, the methods above may not work and you have to come to this way. It is likely that there are some system or program problems on your phone, so you should try some ways to hard reset.

Before trying to fix the iPhone won’t update problem with the ways below, do remember to back up your iPhone, because your iPhone data will be cleared. If you don’t want to try the ways manually, skip to the next method which is using a third-party iOS system recovery program to help.

Reset all settings with your iPhone

This method is to clear all settings and contents in your iPhone to fix some iOS system problems.

  1. Tap Settings > General > Reset > Reset All Settings.

  2. Turn on your phone and try to update to iOS 15 again.

Restore your iPhone with your computer

As for this method, you have to use your computer for the restoring and the latest version of iTunes is required. Here’s the steps to follow:

  1. Launch iTunes.

  2. Connect your iPhone into the computer with the lighting cable.

  3. Select the iPhone icon.

  4. Click “Restore iPhone”. Again, this will clear all data in your phone.

  5. After restoring, turn on your phone and try to update again.

Restore iPhone

Restore and update your iPhone in Recovery Mode

Recovery Mode is a mode that allows you to restore your iPhone as well as update your firmware to the latest version. This way is more forceful than just resetting your phone and can deal with problems like your computer not being able to verify your iPhone or your iPhone screen stuck on an Apple logo. What you need to do is:

  1. Launch iTunes.

  2. Connect your iPhone into the computer with the lighting cable.

  3. Turn on the recovery mode of your iPhone (pressing the buttons in the same way as forcing restart the iPhone, but if you enter the recovery mode successfully, your screen will turn black, showing the lighting cable plugging into the iTunes logo).

  4. iTunes will automatically detect your device and then a notice window pops up.

iTunes Restore or Update

  1. Choose “Update” to update your phone to iOS 15.

  2. Exit the recovery mode after the update finish (the same way as entering recovery mode).

8. Fix update problems and upgrade with iOS system recovery software

Sometimes using a third-party iOS system recovery program to fix iPhone won’t update problem is much easier and more timesaving than trying different ways again and again by yourself. Here we recommend FonePaw iOS System Recovery (opens new window) for you.

FonePaw iOS System Recovery is helpful when you want to solve various iOS system problems including iOS update problems and can help you upgrade or downgrade the iOS system of your phone. It provides three different recovery modes to fix your iOS problems, which are quick recovery mode (free), standard mode, and advanced mode.

iOS System Recovery Intro

Part 2. What You Need to Know About iOS 15 Update

Released on September 20, iOS 15 is a major update of the iOS system that has integrated and improved multiple functions. Here we list some of the highlight features for you to know more about the update:

  • SharePlay in FaceTime: After the iOS 15 update, you will be able to enjoy watching TV and movies, listening to music, and even sharing your screen when you facetime with your family and friends. For playing videos and music, the playback and control are synced, so you will be definitely sharing the same moments at the same time.

  • Focus feature: You can choose different focus modes according to different situations and customize it. You are free to make settings to receive certain notifications when you are in a focus mode and do not be distracted. Your status can also be displayed to your friends through Messengers or other messaging apps to notify them.

  • Redesigned notifications: Notifications display on your lock screen are redesigned to have a larger app icon that can also show contact photos in your Contacts. There will also be a notification summary that collects notifications based on your schedule and priority.

  • Live Text: With the iOS 15 update, text in your Photos can be identified for you to select, copy, look up, and even make a phone call or send emails directly.

There are also improvements in Maps, privacy protection, and more for you to check. Though it’s reported that some problems may arise after the iOS 15 update like the iPhone storage is full. This iOS update is still worth a try.

Part 3. How to Downgrade iPhone System After Update

Unfortunately, your iPhone may not function well after the update, or you really cannot get accustomed to the new iOS system. There is still a way to try – downgrade your iPhone system.

However, think twice before you downgrade, because it will also erase your iPhone. Always remember to back up when you are going to do something that will affect your phone data. Also, the old iOS system available for downgrading is very limited, for the reason that Apple usually disables the sign of the old iOS version soon after an update is released.

If you really make the decision to downgrade, follow the steps below:

Preparations for iOS system downgrade

  • Your iPhone

  • A Computer with the latest iTunes installed

  • The old iOS firmware with signed IPSWs, you can look up and download at

Downgrade iOS system with iTunes

  1. Launch iTunes.

  2. Turn off “Find My iPhone” at Settings > Profile at the top > Find My > Find My iPhone.

  3. Connect your iPhone to iTunes with the charging cable.

  4. Select the iPhone icon.

  5. Press “Shift” (for Windows)/ “Option” (for Mac) and click “Restore iPhone” at the same time.

  6. Choose the firmware to downgrade the phone.

tips Notice:
  • Be very careful when you downgrade your iPhone. Keep the cable connecting and do not do something else to your phone, because mistaken operation can lead to a brick iPhone.

If you think it hard to downgrade your iPhone manually, you can also seek help from a third-party program like FonePaw iOS System Recovery, which can give you clear guidance and do most of the jobs for you. Click How to Downgrade Your iPhone to see more. Besides, keep using iOS 15 and wait for Apple to fix the iOS 15 bugs is also an idea.

Hope this passage can help you solve the iPhone won’t update problem. If you have more concerns, feel free to contact us.

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