The iOS 9 release date was plagued with widespread installation problems. Apple’s servers were slammed with requests and that caused them to meltdown under the pressure. Fortunately, those problems dissipated after 30 minutes or so.
We’re still seeing isolated installation issues though including frozen downloads and and issue that’s preventing users from swiping to update after installing the iOS 9 update on iPhone and iPad. Neither is ideal. Fortunately, there are fixes for both of these issues.
If your iOS 9.2 download or installation locks up, you’ll want to hold down the power button and the home button for 10 seconds. This typically jumpstarts the process.
How to Fix Slide to Update Problem
As for the other issue, we were able to fix the issue simply by unplugging our phone from the computer and iTunes. This isn’t a guaranteed fix but it worked for us and it’s a simple solution to try if you’re unable to do anything when presented with a “Slide to Update” option.
If that doesn’t work, you’ll want to take a look at Apple’s list of official fixes for the well known iOS 9 issue.