When you see the option to Restore or Update, choose Update. iTunes will try to reinstall iOS without erasing your data. Wait while iTunes downloads the software for your device.

After the iOS 8.4 update, my Phone app kept freezing up while the handset itself was running very hot. A full restore fixed the problems; here's how to perform one.

Step-by-step instructions for installing the latest version of iOSu2014and how to reinstall iOS 8, just in case.

If you have an iPhone 6 or iPhone 6 Plus and you lost cellular service and Touch ID functionality today after updating to iOS 8.0.1, here’s the fix: Follow these steps to reinstall iOS 8.0.

From there, connect your iPhone and update to iOS 10 by clicking the phone icon in iTunes and following the onscreen instructions.

Here's Apple's advice: If you still see the Connect to iTunes screen after you restart, you need to reinstall iOS: ...

When you see the option to Restore or Update, choose Update. iTunes will try to reinstall iOS without erasing your data. Wait while iTunes downloads the software for your device.