To date, the version of iOS has been released to 16.4.1 by Apple, and iOS 17 is coming soon. Each update of iOS version brings some different features to all iPhone users. It's pretty easy to install iOS 16 on your iPhone. Unfortunately, lots of iPhone users fail to update their devices to the latest version of iOS. What to do when iPhone says unable to install update? Don't worry! If you're getting this pesky error, here's how to fix iPhone unable to install update and update iOS on your iPhone.

- Part 1. Why Does My iPhone Keep Saying Unable to Install Update?
- Part 2. 8 Solutions to Fix iPhone Unable to Install Update
- Part 3. How to Update iPhone with iTunes/Finder on Computer
Part 1. Why Does My iPhone Keep Saying Unable to Install Update?
If you can't update your iPhone to the latest version of iOS, you might see one of these messages: Unable to Check for Update or Unable to Install Update. You might be unable to update your iPhone or iPad wirelessly — or over the air — for one of these reasons:
1) Your iPhone doesn't support the latest software.
2) There isn't enough available storage space on your iPhone.
3) Your iPhone is connected to an unstable or poor network.
4) Your iPhone isn't able to reach the update server.
5) The update doesn't complete.
Part 2. 8 Solutions to Fix iPhone Unable to Install Update
When the issue of iPhone unable to install update happens, you don't be able to update your iPhone directly anymore. Thankfully, there are a few easy ways to fix this problem.
Solution 1. Force Restart iPhone
If your iPhone says unable to install update, then you can try forcing it to restart. The steps to force restart iPhone depend on the model. Follow the below steps to force restart your iPhone.

For iPhone 8 and Later:
Step 1. Press and quickly release the volume up button.
Step 2. Press and quickly release the volume down button.
Step 3. Press and hold the side button.
Step 4. When the Apple logo appears, release the side button.
For iPhone 7:
Step 1. Press and hold both the volume down button and the Sleep/Wake button at the same time.
Step 2. When the Apple logo appears, release both buttons.
For iPhone 6 and Earlier:
Step 1. Press and hold both the Sleep/Wake button and the Home button at the same time.
Step 2. When the Apple logo appears, release both buttons.
Solution 2. Check the iPhone Storage
Insufficient storage would prevent you from downloading the update. So, you can go to ensure whether there is enough space to download and install an update. To check the iPhone storage, you can follow the below steps.

Step 1. Open the Settings app on your iPhone, then tap General.
Step 2. Under General, tap iPhone Storage to check the storage space.
Solution 3. Charge iPhone to 50%
The time an update takes depends on the size of the update and the number of files on your iPhone. When you're updating over the air, keep your iPhone connected to a power source. If your iPhone runs out of power, connect it to a power source and turn on the device to let the update or restore complete.
Solution 4. Reset Network Settings
You need an internet connection to update your iPhone. When your iPhone is connected to a poor network, it would fail to download and install the update. Then you can go to try another network or reset the network settings on your iPhone.

Step 1. Go to Settings > General > Transfer or Reset iPhone.
Step 2. Tap Reset and select Reset Network Settings.
Solution 5. Quit All Apps on the iPhone
When your iPhone says unable to install update, you can force quit all apps running in the background of your device. In this case, you can solve iPhone unable to install update after quitting all apps. Here are the steps you can follow to close all apps on the iPhone.
For iPhone without Home Button:
Step 1. From the Home screen, swipe up from the bottom of the screen and pause in the middle of the screen.
Step 2. Start to close the app running on your iPhone.
For iPhone with Home Button:
Step 1. Double-click the Home button to show your most recently used apps.
Step 2. Start to close the app running on your iPhone.
Solution 6. Delete and Download Update Again
If you still can't install the latest version of iOS on your iPhone, you can try removing and downloading the update again. This method works for fixing the iPhone unable to update issue. Here's how to get it done.

Step 1. Head to Settings > General > iPhone Storage.
Step 2. In the list of apps, find the downloaded update.
Step 3. Tap the update, then tap Delete Update.
Step 4. Go back to Settings > General and tap Software Update to download the latest update.
Solution 7. Check the iPhone Compatibility
Make sure that your iPhone supports new software. If you don't find the option to update to new software when it becomes available, your iPhone might not support the latest release. So, you need to identify your iPhone model and check whether your iPhone model is on the list of compatible devices of the latest version of iOS. Or you can choose to update the latest version of iOS that is available for you.
Solution 8. Use a Third-party Tool
To fix the issue, you can also use a third-party tool like MagFone iOS System Recovery. It is a multifunctional tool that can help both iOS and iPadOS users to fix various system issues. When your iPhone shows unable to install update, you can try using MagFone iOS System Recovery to fix this issue without losing any data. Let's see how to resolve the iPhone unable to install update via MagFone iOS System Recovery.

Key Features of MagFone iOS System Recovery
* Security Verified. 5,481,347 people have downloaded it.
- Fix various ios issues like screen stuck, mode stuch, and more
- Support updagrading and downgrading iOS without iTunes/Finder
- Offer two modes for resetting iPhone, iPad, and iPod touch
- Assist the entering and exiting of recovery mode for free
Step 1 Connect iPhone to Computer

With the help of a USB cable, connect your iPhone to a computer. Then launch MagFone iOS System Recovery on the computer and click the iOS System Repair button on the main interface of the software.
Step 2 Go to Select Standard Repair

In the next window, there are two options for you to choose. Simply choose Standard Repair and click the Next button. After that, select your device model and put your device into DFU mode by following the onscreen instruction.
Step 3 Download the Firmware Package

Now you have to check whether the device information is correct or not. You can manually correct the wrong information. Then you can click the Download button to start downloading and verifying the firmware package.
Step 4 Fix iPhone Unable to Update

After successfully verifying the firmware package, simply click the Repair button and the software will start fixing the issue on your iPhone. You need to keep your device connected to the computer until the process finishes.
Part 3. How to Update iPhone with iTunes/Finder on Computer
After trying the above methods, you can fix the issues on your iPhone. When your iPhone isn't able to install an update, you can also use your computer to update your device. Here you can make use of iTunes on a Windows PC or the Finder on a Mac to update your iPhone.
Update iPhone Using iTunes

Step 1. Open iTunes on a Windows PC and connect your iPhone to your computer.
Step 2. Click the device button in iTunes toolbar and click Summary > Check for Update.
Step 2. Click Download and Update. Continue by following the onscreen instructions.
Update iPhone Using Finder

Step 1. Launch a Finder window on a Mac, then connect between your iPhone and your computer.
Step 2. Select your device in the left sidebar of the Finder window, then click General > Check for Update.
Step 2. Click Download and Update. Follow the onscreen instructions to install an update.
Conclusion
In this guide, you find all the possible means that you can try to fix the iPhone unable to install update issue. When you cannot install an update on your iPhone, you can choose to use iTunes or the Finder for updating your device. Here we recommend that you use MagFone iOS System Recovery to fix the issue without any hassle.