You are trying to update to the latest version, however, a message pops up and saying that “Unable to Install Update - An error occurred installing iOS 15” just like the user asked above.
Well, this is a quite common problem that happens each year. Here in this guide, I’ll detail all methods that can help you troubleshoot the “An error occurred installing iOS 15” issue. Keep reading.
Note: These methods also apply to fix the error when installing iPadOS 15.
How to Fix Unable to Install Update An Error Occurred Installing iOS 15/iPadOS 15 Error?
The following are all the potential solutions you can have a try to troubleshoot the unable to install iOS 15/iPad OS 15 problem.
Solution 1. Check If Your Device Supports iOS 15
If your device is not compatible with iOS 15, then you may get the “Unable to Install Update - An Error Occurred Installing iOS 15” message. So first make sure that your device is on the supported list.
iOS 15 Supported Devices:
iPhone 12/12 Pro (Max)/12 mini, iPhone SE 2020, iPhone 11/11 Pro (Max), iPhone XS Max/XS/XR/X, iPhone 8/8 Plus, iPhone 7/7 Plus, iPhone 6s/6s Plus, iPhone SE, iPod touch 7
iPadOS 15 Supported Devices:
12.9-inch iPad Pro, 11-inch iPad Pro, 10.5-inch iPad Pro, 9.7-inch iPad Pro, iPad (7th gen), iPad (6th gen), iPad (5th gen), iPad mini (5th gen), iPad mini 4, iPad Air (3rd gen), iPad Air 2
Solution 2. Force Restart Your Device
A force restart can help you dump all junk files of your device and to refresh its memory. It’s a quick trick to fix minor system glitch to get rid of any iOS error. So you can try to force restart your iPhone or iPad when meeting the unable to install iOS 15 error.
Force restart iPhone 8 and later:
Quickly press and release the Volume Up button > Quickly press and release the Volume Down button > Press and hold the Side button until you see the Apple logo.
Force restart iPhone 7/7 Plus:
Press and hold Power button and Volume Down button together > Release both buttons when the Apple logo appears.
Force restart iPhone 6s, SE and earlier
Hold down the Home button and the Power button at the same time > Release both buttons when the Apple logo appears.
Force restart iPad with Face ID:
Press and hold either Volume button and the Top button until the power off slider appears > Drag the slider, then wait 30 seconds for your device to turn off > Press and hold the Top button until you see the Apple logo.
Force restart iPad with Home ID:
Press and hold the Top button until the power off slider appears > Drag the slider, then wait for 30 seconds for your device to turn off > Press and hold the Top button until you see the Apple logo.
Solution 3. Free Up Space
The iOS update requires quite a few free storage space. And the“Unable to Install Update - An Error Occurred Installing iOS 15” message usually pops up due to insufficient memory. You can go to have a check whether there is enough storage space to complete the update. You’d better make sure there is at least 5 GB free storage space.
Go to Settings > General > iPhone Storage to check and delete some useless files. You can also delete some old photos, messages, songs, or infrequently used apps to free up more space.
Solution 4. Delete Downloaded Firmware
The update will be interrupted because of insufficient space, poor network condition, etc. In this case, to let the update complete smoothly, you should delete the incomplete iOS 15 software update file and then restart the iOS update again.
Go to Settings > General > iPhone/iPad Storage > Find and tap the update file > Click Delete Update to make it.
Solution 5. Check Network Connection
The iOS update also requires a stable network connection. The update download may get interrupted because of the poor Internet connection so you get the “Unable to Installing iOS 15” error message.
You can turn off/on Wi-Fi or turn off/on Airplane Mode to refresh the Internet. Besides, you can also try to reset network settings by going to Settings > General > Reset > Reset Network Settings. Then re-enter the password to join the Wi-Fi and try updating again.
Solution 6. Update Your Device via iTunes
If all the above methods cannot help you get rid of the “Unable to Install Update - An Error Occurred Installing iOS 15” message, you may try to update your iPhone or iPad via iTunes.
1. Download and install the latest version of iTunes on your computer.
2. Run iTunes and plug in your device.
3. Click the Device tab > Summary > Click Check for Update button.
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That’s all for how to fix the “Unable to Install Update - An error occurred installing iOS 15”. Did any of these solutions help solve your problem? If so, just share it to help more people. Or if you still have any questions about this issue, just leave a comment to let us know.