The exact symptom points to the cause. If the update never appears, your model may already be on the last version it supports (Solution 1). If it hangs on "Checking for update", it is the network or the servers (Solution 3). If it fails during installation, it is almost always free space - and iOS needs considerably more room than the file size (Solution 2). Updating through a computer (Solution 6) gets around most stubborn cases.
What causes this problem
- Not enough free space: iOS needs several gigabytes beyond the update size to unpack and install it.
- The iPhone model has reached the last version it supports and receives no further updates.
- An unstable Wi-Fi connection, or the update started off Wi-Fi.
- Battery below 50% with the phone unplugged - iOS blocks installation in that state.
- Apple's servers under load in the first hours after a release.
- A configuration or beta profile installed, holding the device on a different update channel.
- Check under Settings > General > About which version you have today and the exact model.
- Look at free space under Settings > General > iPhone Storage. Less than 6 GB free usually stalls a large update.
- Plug the iPhone in and connect to Wi-Fi before trying again - the system requires both conditions.
- Back up before updating. A failed update is rare, but a backup is what separates a scare from a real problem.
Solutions, in the order to try them
1Confirm your model still receives the update
This check saves hours of pointless attempts. Every model reaches a point where Apple ends support, and from then on the update simply does not appear - nothing is broken.
- Open Settings > General > About and note the Model Name and iOS Version.
- Compare it against the compatibility list for the version you want, on Apple's support page.
- If your model is not listed, the device is on the last version it gets - and still receives security fixes for a while.
- If it is listed, move on to the solutions below.
2Free up space - the most common installation failure
The update downloads, but installing it needs extra room to unpack. That is why a 4 GB update can fail even with 5 GB free.
- Open Settings > General > iPhone Storage and read the recommendations at the top.
- Delete long videos and empty the Recently Deleted album in Photos.
- In Messages, use Review Large Attachments to remove old videos from conversations.
- Uninstall large apps you do not use - the screen lists them by size.
- Leave at least 10 GB free before trying again.
3Fix a hang on "Checking for update"
That message means the iPhone is trying to reach Apple's servers and not getting through. It is usually the network - or queueing, in the first hours of a release.
- Switch Wi-Fi off and on, and open a website to confirm the connection works.
- Force restart the device: press and release Volume Up, press and release Volume Down, hold the side button until the Apple logo appears.
- If the version has just been released, wait a few hours - servers are congested in the first days.
- If you are on a corporate network or using a VPN, try another network: filters can block the update servers.
4Delete the downloaded update and get it again
A corrupted update file makes installation fail at the same point every time, without explaining why. Removing and re-downloading resolves it.
- Open Settings > General > iPhone Storage.
- Find the entry named after the iOS version in the list (it appears like an app).
- Tap it and choose Delete Update.
- Go back to Settings > General > Software Update and download again.
5Remove configuration or beta profiles
If you have joined the beta programme, or installed a profile from a company or school, the device may be held on a different update channel.
- Open Settings > General > VPN and Device Management.
- If any profile is listed, open it and see what it is.
- Remove beta profiles you no longer use and restart the device.
- Under Settings > General > Software Update > Beta Updates, confirm it is set to Off.
6Update through a computer
This is the route that gets around almost every stubborn case: updating from a computer does not depend on the iPhone's free space in the same way and does not go through the same servers.
- Connect the iPhone to the computer with the cable.
- Open Finder (macOS) or the Apple Devices app / iTunes (Windows).
- Select the device, click Check for Update and then Update.
- Choose Update, never Restore - the second option erases the device.
- Keep the cable connected until the iPhone restarts by itself and returns to the home screen.
Applies to
| System | Status |
|---|---|
| iOS 16 to 18 | Confirmed |
| iOS 15 and earlier | Confirmed |
| iPad and iPadOS | The same steps apply, with the menus in the same places |
Menu names can change slightly between versions. If a step above does not match what you see on screen, the official support page from the manufacturer has the most current wording for your version.
Frequently asked questions
Last checked: Aug 22, 2026 · We review this guide whenever the manufacturer changes the process.