What do you do when your iPhone apps won't open?

Answer 1

If your apps close on launch (that is, you tap on the app icon and you're immediately taken back to the home screen), try the following steps:

1. Attempt to open and close the apps. Double-tap on your home button. If you have iOS 4 through 6.1.4, you will see a bar open up at the bottom of your screen with your recently-used apps in them. You can swipe from right to left to see more. Tap and hold on the icon of the app that is giving you trouble until it jiggles. Press the red circular button that appears in the upper left corner of this icon to close that app. Then try reopening it.
2. If you have iOS 7, follow the same steps as above, except after double-tapping your home button, find the app icon with the preview of its open window above it. Then swipe upwards to close that app. Then try reopening it.
3. If that didn't help, see if you can open the App Store and check for updates. If there is an update available for your app, try and get it. See if it helps.
4. Power off and power your phone on again, for at least one minute. You should be doing this at least once a week if you use your phone lightly, and at least once every few days if you're a heavy user. To completely power your phone off, press and hold on the top (sleep/wake) button on your phone. Then, swipe your finger from left to right across the red "slide to power off" bar that appears on screen.
5. If that doesn't help, attempt to restore your iPhone in iTunes. Note that doing so will ERASE YOUR iPHONE completely, so be sure all your information is saved first. You can try and restore from a backup and see if the issues persist, but if so, try restoring again and setting up the phone as new.
6. If the issues are STILL persisting, bring your iPhone into your nearest Apple Store with a Genius Bar appointment (you can make one online; see the Related Links); they can run diagnostics and provide you with further assistance.