If you’re updating your iOS device with OTA updates, be aware that sometimes they won’t install right away. The Install Now button might also be greyed out and unresponsive- don’t worry! This happens when there’s an update waiting for download in iTunes or on Apple servers so just wait until this window pops up again before tapping “Begin Update.”
This is a tricky one. Even though your iOS device may have finished downloading apps and other iCloud content, the error message reading “You can install this update when it’s done restoring from its backup” will continue to display unless you tap cancel in order for things to go back into normal mode!
The easiest way to fix this issue is by turning off your device and then back on again. Users have reported that resetting their phone by holding down both buttons until it reboots worked for them as well, so try those methods first if you’re having trouble!